Absence of hMLH1 or hMSH2 Expression as a Stage-Dependent Prognostic Factor in Sporadic Colorectal...

ORIGINAL ARTICLE – COLORECTAL CANCER

Absence of hMLH1 or hMSH2 Expression as a Stage-DependentPrognostic Factor in Sporadic Colorectal Cancers

Ji Won Park, MD1, Hee Jin Chang, MD1, Sohee Park, PhD2, Byung Chang Kim, MD1, Dae Yong Kim, MD1,

Ji-Yeon Baek, MD1, Sun Young Kim, MD1, Jae Hwan Oh, MD1, Hyo Seong Choi, MD1, Sung Chan Park, MD1,

and Seung-Yong Jeong, MD3

1Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea;2Cancer Biostatistics Branch, Research Institute, National Cancer Center, Goyang, Republic of Korea; 3Department of

Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea

ABSTRACT

Background. The predictive role of mismatch repair

(MMR) status for survival after sporadic colorectal cancer

remains a point of controversy. This study was designed to

test the prognostic value of MMR status in sporadic colo-

rectal cancers.

Methods. The study included 318 patients with sporadic

colorectal cancer who underwent primary tumor resection.

MMR status was determined by the immunohistochemical

analysis of hMLH1 and hMSH2 expression.

Results. Thirty-six carcinomas (11.3%) showed abnormal

MMR protein expression (22 hMLH1 negative and 14

hMSH2 negative) and were classified as MMR-defective

tumors. An MMR defect was strongly associated with a

reduced likelihood of lymph node (odds ratio, 0.32; 95%

confidence interval [95% CI], 0.13–0.75) or distant organ

metastases at diagnosis (odds ratio, 0.07; 95% CI, 0.01–

0.62), independent of the clinicopathological features.

Overall survival was significantly better in patients with

MMR-defective tumors than in those with MMR-intact

tumors (P = 0.013). In the subgroup analysis by stage,

adjusted for other potential confounding variables, MMR

status was not a statistically significant prognostic factor in

stage I and II patients, while the MMR defect predicted a

significantly better overall survival in stage III and IV

patients (adjusted hazard ratio, 0.23; 95% CI, 0.06–0.97;

P = 0.045).

Conclusions. At initial diagnosis, metastases were found

at lower rates in MMR-defective tumors. MMR status may

be a stage-dependent prognostic factor in patients with

sporadic colorectal cancer.

Studies conducted in the past two decades have

identified two well-defined pathways for colorectal carci-

nogenesis. The first and more common pathway is the

suppressor pathway, involving mutations in key oncogenes

and the inactivation of tumor suppressor genes (APC, p53,

DCC, Samd2, and Smad4). The second is the mutator

pathway, in which the inactivation of mismatch repair

(MMR) genes (mainly hMLH1 and hMSH2) is involved in

the development of tumors in patients with hereditary

nonpolyposis colorectal cancer (HNPCC). Approximately

80% of HNPCC can be ascribed to germ line mutations in

either hMLH1 or hMSH2.1 DNA MMR deficiency is also a

feature of approximately 15% of sporadic colorectal

cancers.2

Although polymerase chain reaction amplification of

microsatellite repeats remains the reference method for the

recognition of MMR-defective tumors, this approach is

clearly not feasible in routine pathology work. Some

studies have demonstrated that it is possible to identify

tumors with a defective MMR system by immunochemistry

and that this technique could be a useful alternative to

molecular biological methods.3,4

The biological behavior of colorectal cancers with

MMR deficiency seems to differ from that of cancers with

intact MMR.5 Paradoxically, despite a high risk of

metachronous disease in patients harboring germ line

mutations, their prognosis seems better than that of patients

with MMR-competent tumors.6 This also seems to be a

� Society of Surgical Oncology 2010

First Received: 17 September 2009;

Published Online: 12 June 2010

H. J. Chang, MD

e-mail: [email protected]

Ann Surg Oncol (2010) 17:2839–2846

DOI 10.1245/s10434-010-1135-8

feature of sporadic colorectal cancers that are MMR

deficient.7,8

Several studies that used microsatellite instability (MSI)

tests have shown that MSI contributes to improved survival

by its association with a lower pathological stage at diag-

nosis and as a stage-for-stage predictor of a more favorable

outcome.9,10 However, there have been few studies of the

relationship between MMR status and survival in patients

with sporadic colorectal cancers. The aim of this study was

to investigate the prognostic value of MMR status.

MATERIALS AND METHODS

Study Population

Five hundred seven consecutive patients underwent

colorectal surgery for primary colorectal cancer at the

National Cancer Center, Korea, between May 2001 and

December 2003. Patients were excluded from the study if

they had received preoperative chemoradiotherapy

(n = 142), had a family history of colorectal cancer

(n = 43), or underwent transanal excision (n = 4). Patients

with family histories of colorectal cancer were defined as

patients with familial adenomatous polyposis or HNPCC,

or patients with first-degree relatives with HNPCC-asso-

ciated cancers (cancer of the colon, endometrium, small

bowel, ureter, or renal pelvis). Finally, the study included

318 patients for analysis. Our study was performed in

accordance with the Declaration of Helsinki. Informed

consent was obtained from all patients. The research pro-

tocol was approved by the institutional review board of the

National Cancer Center, Korea (NCCNCS-07-073).

Tumors were classified and staged according to the sixth

edition of the TNM Classification of the American Joint

Committee on Cancer.11 Thirty-six cases were classified as

stage I, 94 as stage II, 114 as stage III, and 74 as stage IV.

One hundred ninety-one of the patients were men (59%)

and 127 were women (41%), with a mean ± standard

deviation age of 60.5 ± 11.8 years (range, 27–87 years).

Eighty-eight tumors were located in the right colon (from

the cecum to the transverse colon) and 230 in the left colon

(from the descending colon to the rectum).

Histopathological Evaluation

Histological sections of the tumors were examined and

the following features recorded: tumor location, size, depth

of invasion, lymphatic invasion, perineural invasion, pe-

ritumoral lymphocytic infiltration, and pattern of growth at

the tumor periphery. The peritumoral lymphocytic infil-

tration was regarded as conspicuous when there was a

distinct cuff of lymphocytes at the margin of the tumor.12

The growth pattern of the tumor was recorded as ‘‘push-

ing’’ when the advancing edge of the tumor was well

defined under low-power magnification and as ‘‘infiltrat-

ing’’ when there was an irregular infiltration of tumor cells

at the advancing front.12

Assessment of MMR Status by Immunochemistry

One block of 10% formalin-fixed, paraffin-embedded

carcinoma tissue was selected from each patient. In all

cases, this block comprised an area of normal colon

mucosa adjacent to the tumor. Immunochemical staining

was performed by the Labeled Streptavidin Biotin kit

(Dako, Glostrup, Denmark). The mouse antihuman mono-

clonal antibodies used were directed against hMLH1 (clone

G168-15, diluted 1:40; BD Pharmingen, San Diego, CA)

and hMSH2 (clone FE11, diluted 1:300; Oncogene

Research Products, Boston, MA). Antigen retrieval was

performed by steam heating in 1 mM EDTA for 30 min-

utes. As a negative control, nonimmune serum was

substituted for the primary antibody. The nuclei of normal

colonic epithelial cells and lymphocytes are strongly

stained for hMLH1 and hMSH2. This was used as a

positive internal control for the staining of these proteins.

Loss of expression was recorded when nuclear staining was

completely absent in all malignant cells. Diffuse nuclear

staining of these proteins in tumor cells was interpreted as

‘‘intact’’ (Fig. 1).

Treatment

The types of surgery were low anterior resection

(n = 97), anterior resection (n = 86), right hemicolectomy

(n = 82), subtotal or total colectomy (n = 18), left hemi-

colectomy (n = 12), Hartmann procedure (n = 12), and

abdominoperineal resection (n = 11). Patients with tumors

that had developed beyond stage II were considered for

adjuvant chemotherapy. Of the 318 patients, 258 (81.1%)

received adjuvant chemotherapy, which commenced

approximately 3 to 6 weeks after curative resection. Flu-

orouracil-based adjuvant chemotherapy was used as the

adjuvant chemotherapy regimen in 242 patients, and oxa-

liplatin- or irinotecan-based adjuvant chemotherapy was

used in 16 patients.

Follow-up

All patients underwent standardized follow-up, com-

prising a physical examination, complete blood count, liver

function tests, serum carcinoembryonic antigen (CEA)

tests, and chest radiographs every 3 months for the first

2 years and every 6 months thereafter, as well as

2840 J. W. Park et al.

abdominal and pelvic computed tomographic scanning

every 6 months. Colonovideoscopic examinations were

carried out 1 year after surgery, then once every 2 years.

Statistical Analysis

Statistical analysis was performed with SPSS software

(version 14.0; SPSS, Chicago, IL). The association

between the clinicopathological features and MMR status

was analyzed with Fisher’s exact test for categorical vari-

ables and with an unpaired Student’s t-test for continuous

variables. The association between MMR status and

metastasis to regional lymph nodes or distant organs was

evaluated with multivariate logistic regression including all

pathological variables. The period from the date of resec-

tion to the date of death was used for the survival analysis.

The log rank test was used to compare the Kaplan–Meier

survival curves. To test MMR status as a prognostic factor

for overall survival, we used a multivariate analysis

according to the Cox proportional hazard model. The

covariates that were statistically significant in the univari-

ate analysis were then included in the multivariate analysis.

Confounding exists between MMR status, stage of disease,

and survival outcomes. The significance of the above fac-

tors on overall survival was assessed by stratified

multivariate Cox regression analysis, with the stage at

diagnosis as the strata (stage I, II and stage III, IV). Two-

sided P values of \0.05 were considered statistically

significant.

RESULTS

Demographics and Clinicopathological Features

According to MMR Status

Of 318 patients with primary colorectal cancers, 36

(11.3%) had MMR-defective cancers (22 hMLH1 negative

and 14 hMSH2 negative). Table 1 shows the demo-

graphics and clinicopathological features of patients with

MMR-intact cancers compared with those of patients with

MMR-defective cancers. MMR-defective tumors had a

significantly lower tumor stage at the time of diagnosis

(P \ 0.001). They showed significantly lower N stages and

M stages (P = 0.007 and P = 0.002, respectively). MMR-

defective tumors developed at significantly higher fre-

quencies at proximal sites than did MMR-intact tumors

(52.8% vs. 24.5%, respectively; P \ 0.001) and tended to

be larger (mean ± standard deviation, 6.3 ± 2.3 cm vs.

5.2 ± 2.1 cm, respectively; P = 0.004). Lymphocytic

infiltration was more frequently observed in patients with

MMR-defective tumors (P \ 0.001). MMR-defective

tumors displayed infiltrative borders and lymphatic inva-

sion less frequently than did MMR-intact tumors (P =

0.009, P = 0.011, respectively).

Likelihood of Metastasis at Diagnosis

On univariate analysis, the factors related to lymph node

metastasis were MMR status, CEA, tumor invasion, tumor

FIG. 1 Immunohistochemically

detected expression of hMLH1

and hMSH2 in colorectal

adenocarcinomas. Moderately

differentiated adenocarcinoma

showing complete loss of hMLH1

expression (a) and intact hMSH2

expression (b). Poorly

differentiated adenocarcinoma

showing intact hMLH1

expression (c) and complete loss

of hMSH2 expression (d)

MMR Defect in Sporadic Colorectal Cancer 2841

grade, lymphatic invasion, lymphocytic infiltration, peri-

neural invasion, and tumor border. Multivariate logistic

analysis revealed that an MMR defect was associated with

a reduced likelihood of lymph node metastasis (odds ratio,

0.32; 95% confidence interval [95% CI], 0.13–0.75;

P = 0.009).

On univariate analysis, factors related to distant metas-

tasis were MMR status, CEA, tumor invasion, nodal status,

lymphatic invasion, lymphocytic infiltration, perineural

invasion, and tumor border. Multivariate logistic analysis

revealed that an MMR defect was strongly associated with

a reduced likelihood of distant metastasis (odds ratio, 0.07;

95% CI, 0.01–0.62; P = 0.017).

Survival Analysis

One hundred five deaths were registered among 318

patients over a median follow-up of 78 months (range, 51–

99 months). Median length of follow-up of 295 patients

with full follow-up was significantly longer than that of 23

patients with loss of follow-up (50.9 months vs.

38.3 months; P \ 0.001). By Kaplan-Meier analysis, the

overall survival of patients with MMR-defective tumors

was found to be significantly better than that of patients

with MMR-intact tumors (P = 0.013; Fig. 2). After strat-

ification by tumor stage (Fig. 3), the advantage in overall

survival for patients with MMR-defective tumors was not

maintained in stage I and II disease. In stage III and IV

disease, overall survival was significantly better in patients

with MMR-defective tumors than in those with MMR-

intact tumors (P = 0.026).

On univariate analysis, MMR status, preoperative CEA,

tumor stage, tumor grade, lymphatic invasion, perineural

invasion, lymphocytic infiltration, tumor border, and

postoperative chemotherapy were statistically significant

predictors of outcome. From the multivariable Cox pro-

portional hazard model on all patients, MMR status was not

a statistically significant predictor when the effect was

adjusted for potential confounding variables that showed

significant univariate association with overall survival

TABLE 1 Demographics and clinicopathologic features of MMR-

defective and MMR-intact tumors

Characteristic MMR intact MMR defectivea P

No. of patients 282 (88.7%) 36 (11.3%)

Age at diagnosis (y) 60.6 ± 11.7 60.3 ± 12.1 0.921

Sex 0.892

Male 169 (59.9%) 22 (61.1%)

Female 113 (40.1%) 14 (38.9%)

Tumor site \0.001

Proximal 69 (24.5%) 19 (52.8%)

Distal 213 (75.5%) 17 (47.2%)

Preoperative CEA 0.959

\5 ng/mL 197 (69.9%) 25 (69.4%)

C5 ng/mL 85 (30.1%) 11 (30.6%)

Tumor stage \0.001

I 34 (12.1%) 2 (5.6%)

II 73 (25.9%) 21 (58.3%)

III 102 (36.2%) 11 (33.3%)

IV 73 (25.9%) 1 (2.8%)

Tumor invasion 0.377

T1 12 (4.3%) 1 (2.8%)

T2 30 (10.6%) 1 (2.8%)

T3 170 (60.3%) 22 (61.1%)

T4 70 (24.8%) 12 (33.3%)

Nodal status 0.007

N0 113 (40.1%) 23 (63.9%)

N1 82 (29.1%) 10 (27.8%)

N2 87 (30.9%) 3 (8.3%)

Distant metastases 0.002

M0 219 (77.7%) 36 (100%)

M1 63 (22.3%) 0

Liver metastases 0.002

Negative 223 (78.0%) 36 (100%)

Positive 63 (22.0%) 0 (0%)

Tumor size (cm) 5.2 ± 2.1 6.3 ± 2.3 0.004

Tumor cell type 0.549

Nonmucinous 259 (91.8%) 32 (88.9%)

Mucinous 23 (8.2%) 4 (11.1%)

Tumor grade 0.299

WD/MD 246 (87.2%) 29 (80.6%)

PD 36 (12.8%) 7 (19.4%)

Lymphatic invasion 0.011

Negative 110 (39.0%) 22 (61.1%)

Positive 172 (61.0%) 14 (38.9%)

Perineural invasion 0.133

Negative 184 (65.2%) 28 (77.8%)

Positive 98 (34.8%) 8 (22.2%)

Lymphocytic infiltrationb \0.001

Negative 253 (91.0%) 23 (63.9%)

Positive 25 (9.0%) 13 (36.1%)

TABLE 1 continued

Characteristic MMR intact MMR defectivea P

Tumor border 0.009

Pushing 147 (52.1%) 27 (75.0%)

Infiltrative 135 (47.9%) 9 (25.0%)

MMR mismatch repair, CEA carcinoembryonic antigen, WD well

differentiated, MD moderately differentiated, PD poorly differenti-

ated. Data are expressed as n (%) or mean ± standard deviationa Loss of MLH1 or MSH2 expressionb Total of 314 cases available


(adjusted hazard ratio, 0.58; 95% CI, 0.22–1.53;

P = 0.271). However, when analyzed separately by stage

at diagnosis, the MMR defect was shown to predict a

significantly better overall survival in stage III and IV

patients (adjusted hazard ratio, 0.23; 95% CI, 0.06–0.97;

P = 0.045), but this trend was not observed in stage I and

II patients (Table 2).

DISCUSSION

This study showed that 11.2% of patients with sporadic

colorectal cancers had an MMR defect, whereas the MMR

defect rate has been reported to be 9% to 20% in other

studies.2,13–15 This discrepancy in the MMR defect rate

may be attributable to the inclusion criteria or the analysis

methods used. The inclusion criteria may be an especially

important factor in explaining this discrepancy. One study,

which excluded familial adenomatous polyposis and

HNPCC, showed 20.4% MSI-positive cancers.13 Another

study, which excluded familial adenomatous polyposis,

HNPCC, and patients with first-degree relatives with can-

cers associated with HNPCC (cancer of the colon,

endometrium, small bowel, ureter, or renal pelvis), repor-

ted that 9.1% of cancers were MSI positive.14 Our study

showed a lower rate (11.3%) because we used an extended

definition of sporadic colorectal cancer, excluding patients

with cancers associated with HNPCC in first-degree rela-

tives. The analysis methods may also have affected the

detection rate of MMR-defective tumors.16 The markers

used (the five National Cancer Institute–recommended

markers, or more or fewer) and the definition of MSI-H

(30% or 40% positive, or positive for one specific marker)

may have affected MSI testing, whereas the positive cutoff

values or staining conditions, such as the antigen retrieval

method, could have affected the immunohistochemical

detection of MMR defects.17,18

Although MSI testing was not examined in this study,

most published studies have demonstrated that two anti-

bodies directed against the hMLH1 and hMSH2 proteins

allow a diagnosis of MSI with high specificity (95% to

100%) and usually with high sensitivity, although in some

studies, this sensitivity was between 70% and 80%.3,4,19–27

1.0

0.8

0.6

0.4

0.2

MMR defectMMR intactP = 0.013

Month0

36282

10

36259

20

33235

30

33220

40

33211

50

33204

60

30196

70

24161

80

1565

90

521

100

MMR defectMMR intact

Overall Survival rate

FIG. 2 Overall survival of 318 patients with sporadic colorectal

cancer according to mismatch repair (MMR) status (MMR defective

vs. MMR intact)

FIG. 3 Overall survival of patients with sporadic colorectal cancer

stratified by the stage, according to mismatch repair (MMR) status

(MMR defective vs. MMR intact). (a) stage I, II; (b) stage III, IV


In a study combining the results of 16 series, representing

3494 cases, the immunohistochemical analysis of the MSI-

H phenotype had a sensitivity of 92.4% and a specificity of

99.6%.25 However, in purely hereditary cases, the sensi-

tivity of immunohistochemistry in predicting germ line

mutations in the MLH1 and MSH2 genes drops to 82%,

largely because of its lower sensitivity in detecting MLH1

mutations (74%). In the hereditary context, approximately

half the mutations in the MLH1 gene are missense muta-

tions, which usually result in mutant proteins that are

catalytically inactive but antigenically intact. Moreover,

even protein-truncating mutations in MLH1 can result in a

protein that reacts with the commonly used anti-MLH1

antibody.28 These observations explain the lower sensitiv-

ity of the immunohistochemical analysis in predicting germ

line mutations in MLH1. Unlike its efficacy in detecting

hereditary cancers, immunohistochemistry has an overall

sensitivity of approximately 90% and a specificity of[99%

in detecting MSI-positive colorectal tumors in patients with

sporadic colorectal cancer. Most patients ([90%) with

sporadic colorectal cancers with MMR abnormalities

acquire an MSI phenotype via the hypermethylation of the

TABLE 2 Multivariable

analysis for the prognostic

factors on overall survival,

separately by stage at diagnosis

MMR mismatch repair, CEAcarcinoembryonic antigen, WDwell differentiated, MDmoderately differentiated, PDpoorly differentiateda Oxaliplatin- or irinotecan-

based adjuvant chemotherapy

Prognostic factor No. of

patients

Hazard ratio 95% confidence

interval

P

Stage I and II

MMR status 0.573

Intact 107 1 (reference)

Defective 23 1.47 0.38–5.65

Preoperative CEA 0.018

\5 ng/mL 112 1 (reference)

C5 ng/mL 18 4.31 1.29–14.36


Negative 88 1 (reference)

Positive 42 1.24 0.36–4.34



Positive 21 1.93 0.52–7.22

Stage III and IV

MMR status 0.045

Intact 175 1 (reference)

Defective 13 0.23 0.06–0.97

Preoperative CEA \0.001

\5 ng/mL 110 1 (reference)

C5 ng/Ml 78 2.75 1.72–4.39

Tumor grade 0.039

WD/MD 154 1 (reference)

PD 34 1.71 1.03–2.85



Positive 144 2.17 1.10–4.28



Positive 85 1.39 0.86–2.24

Tumor border 0.153

Pushing 85 1 (reference)

Infiltrative 103 1.45 0.87–2.41

Postoperative chemotherapy \0.001

No 22 1 (reference)

Fluorouracil-based 151 0.25 0.13–0.47

Othera 15 0.61 0.27–1.38


promoter region of the MLH1 gene.29–31 Such a defect

usually results in the complete silencing of transcription

and the loss of protein expression. Thus, a far higher per-

centage of sporadic MSI-positive colorectal cancers show

negative MLH1 staining with immunohistochemistry. Even

if molecular MSI testing remains the current gold standard

for assessing DNA MMR competency in tumors, all these

studies confirm that the immunohistochemical detection of

hMLH1 and hMSH2 is a sensitive, rapid, and cost-effective

method, especially for sporadic colorectal cancer. For this

reason, we used immunohistochemistry as a tool for

detecting MMR deficiency.

The use of MSI in predicting the prognoses of patients

with colorectal cancer is controversial. Although several

studies have suggested better survival in patients with MSI-

H tumors, other studies could not confirm these find-

ings.8–10,32–36 MSI-positive tumors also have contradictory

prognostic features, such as poor differentiation and pe-

ritumoral lymphocytic infiltration. Only a few studies of

MMR status have been based on immunohistochemical

data as a prognostic factor. One study showed that MMR

status was an independent prognostic factor in stage II and

III disease.37 Another study demonstrated that MMR status

determined by immunohistochemistry is an independent

predictive factor of a good prognosis in T3N0M0 colon

cancer.38 However, our analysis of survival conducted in

patients with all stages of sporadic colorectal cancer sug-

gests that an MMR defect is a stage-dependent predictor of

better survival. In advanced colorectal cancer (stage III and

IV), MMR status was a statistically significant prognostic

factor, but not in stage I and II disease.

The advantage in overall survival for patients with an

MMR defect is partly dependent on the earlier stage at

which these cancers are diagnosed. These findings are

consistent with the results of a recent study conducted on a

large, single-institution series of consecutive and unse-

lected Italian patients. That study found that the lower

metastatic risk of MSI-H cancers is to be the main deter-

minant of their prognostic advantage.39 Given that patients

with MMR-defective tumors have a reduced likelihood of

metastasis at diagnosis, these findings clearly indicate that

the reduced metastatic potential of the primary tumor is the

one mechanism for the survival advantage of patients with

MMR-defective colorectal cancer. However, interestingly,

our results showed that an MMR defect predicted a sta-

tistically significantly better overall survival only in stage

III and IV disease. According to stage, MMR status had

different prognostic features. MMR status may be useful

for predicting the prognosis in advanced colorectal cancer.

Some studies also showed improved survival of MSI-H

tumors in stage III.37,40

Our study had the limitation of insufficient sample size

for definite conclusions. In the survival analysis for each

stage, only the survival curves for stage III disease seemed

to be divergent in favor of MMR-absent patients, but there

were no statistically significant differences (data not

shown). However, the estimated power did not obtain an

adequate level (41.33%). Further studies with larger sam-

ple sizes are needed to to be able to draw more definite

conclusions for each stage.

The accurate detection of lymph node and distant

metastases is critical in the analysis of the relationship

between MMR status and stage. Adequate lymph node

dissection and the meticulous pathological assessment of

lymph nodes have provided the most accurate clinico-

pathological staging of the disease. We have usually

performed a high ligation for left-colon and rectal cancers

and an extended lymph node dissection near the superior

mesenteric vessels for right-colon cancers. Entire colorec-

tal cancer specimens were examined two to three times to

obtain as many lymph nodes as possible. In our study, the

median number of collected lymph nodes was 23 (range, 7–

253). Because the imaging modalities for distant metastasis

have improved, more metastases are detected than were

detected in the 1990s. Metastases are more likely to be

undetected at the initial diagnosis among MMR-intact

patients who have a much greater likelihood of metastasis.

In conclusion, metastases were found at a lower rate in

MMR-defective tumors at initial diagnosis. MMR status

may be a stage-dependent prognostic factor in patients with

sporadic colorectal cancer.

ACKNOWLEDGMENT This study was supported by a grant from

the National Cancer Center of Korea (NCC-0910160).

REFERENCES

1. Lynch HT, de la Chapelle A. Genetic susceptibility to non-pol-

yposis colorectal cancer. J Med Genet. 1999;36:801–18.

2. Liu B, Nicolaides NC, Markowitz S, et al. Mismatch repair gene

defects in sporadic colorectal cancers with microsatellite insta-

bility. Nat Genet. 1995;9:48–55.

3. Lindor NM, Burgart LJ, Leontovich O, et al. Immunohisto-

chemistry versus microsatellite instability testing in phenotyping

colorectal tumors. J Clin Oncol. 2002;20:1043–8.

4. Thibodeau SN, French AJ, Roche PC, et al. Altered expression of

hMSH2 and hMLH1 in tumors with microsatellite instability and

genetic alterations in mismatch repair genes. Cancer Res.1996;56:4836–40.

5. Jass JR. Pathology of hereditary nonpolyposis colorectal cancer.

Ann N Y Acad Sci. 2000;910:62–73.

6. Sankila R, Aaltonen LA, Jarvinen HJ, Mecklin JP. Better survival

rates in patients with MLH1-associated hereditary colorectal

cancer. Gastroenterology. 1996;110:682–7.

7. Bubb VJ, Curtis LJ, Cunningham C, et al. Microsatellite insta-

bility and the role of hMSH2 in sporadic colorectalcancer.

Oncogene. 1996;12:2641–9.

8. Samowitz WS, Curtin K, Ma KN, et al. Microsatellite instability

in sporadic colon cancer is associated with an improved prognosis

at the population level. Cancer Epidemiol Biomarkers Prev.2001;10:917–23.


9. Benatti P, Gafa R, Barana D, et al. Microsatellite instability and

colorectal cancer prognosis. Clin Cancer Res. 2005;11:8332–40.

10. Gryfe R, Kim H, Hsieh ET, et al. Tumor microsatellite instability

and clinical outcome in young patients with colorectal cancer. NEngl J Med. 2000;342:69–77.

11. Greene FL, Page DL, Fleming ID, et al. AJCC cancer stagingmanual. New York: Springer-Verlag, 2002.

12. Jass JR, Love SB, Northover JM. A new prognostic classification

of rectal cancer. Lancet. 1987;1:1303–6.

13. Gafa R, Maestri I, Matteuzzi M, et al. Sporadic colorectal ade-

nocarcinomas with high-frequency microsatellite instability.

Cancer. 2000;89:2025–37.

14. Jeong SY, Shin KH, Shin JH, et al. Microsatellite instability and

mutations in DNA mismatch repair genes in sporadic colorectal

cancers. Dis Colon Rectum. 2003;46:1069–77.

15. Thibodeau SN, Bren G, Schaid D. Microsatellite instability in

cancer of the proximal colon. Science. 1993;260:816–9.

16. Shia J, Ellis NA, Klimstra DS. The utility of immunohisto-

chemical detection of DNA mismatch repair gene proteins.

Virchows Arch. 2004;445:431–41.

17. Laghi L, Bianchi P, Malesci A. Differences and evolution of the

methods for the assessment of microsatellite instability. Onco-gene 2008;27:6313–21.

18. Muller W, Burgart LJ, Krause-Paulus R, et al. The reliability of

immunohistochemistry as a prescreening method for the diag-

nosis of hereditary nonpolyposis colorectal cancer (HNPCC)—

results of an international collaborative study. Fam Cancer.2001;1:87–92.

19. Cawkwell L, Gray S, Murgatroyd H, et al. Choice of management

strategy for colorectal cancer based on a diagnostic immunohis-

tochemical test for defective mismatch repair. Gut. 1999;45:409–

15.

20. Chaves P, Cruz C, Lage P, et al. Immunohistochemical detection

of mismatch repair gene proteins as a useful tool for the identi-

fication of colorectal carcinoma with the mutator phenotype. JPathol. 2000;191:355–60.

21. Dieumegard B, Grandjouan S, Sabourin JC, et al. Extensive

molecular screening for hereditary non-polyposis colorectal

cancer. Br J Cancer. 2000;82:871–80.

22. Iino H, Simms L, Young J, et al. DNA microsatellite instability

and mismatch repair protein loss in adenomas presenting in

hereditary non-polyposis colorectal cancer. Gut. 2000;47:37–42.

23. Jass JR. hMLH1 and hMSH2 immunostaining in colorectal

cancer. Gut. 2000;47:315–6.

24. Lanza G, Gafa R, Maestri I, et al. Immunohistochemical pattern

of MLH1/MSH2 expression is related to clinical and pathological

features in colorectal adenocarcinomas with microsatellite insta-

bility. Mod Pathol. 2002;15:741–9.

25. Rigau V, Sebbagh N, Olschwang S, et al. Microsatellite insta-

bility in colorectal carcinoma. The comparison of

immunohistochemistry and molecular biology suggests a role for

hMSH6 [correction of hMLH6] immunostaining. Arch PatholLab Med. 2003;127:694–700.

26. Salahshor S, Koelble K, Rubio C, Lindblom A. Microsatellite

instability and hMLH1 and hMSH2 expression analysis in

familial and sporadic colorectal cancer. Lab Invest. 2001;81:535–

41.

27. Ward R, Meagher A, Tomlinson I, et al. Microsatellite instability

and the clinicopathological features of sporadic colorectal cancer.

Gut. 2001;48:821–9.

28. Wahlberg SS, Schmeits J, Thomas G, et al. Evaluation of

microsatellite instability and immunohistochemistry for the pre-

diction of germ-line MSH2 and MLH1 mutations in hereditary

nonpolyposis colon cancer families. Cancer Res. 2002;62:3485–

92.

29. Cunningham JM, Christensen ER, Tester DJ, et al. Hyperme-

thylation of the hMLH1 promoter in colon cancer with

microsatellite instability. Cancer Res. 1998;58:3455–60.

30. Herman JG, Umar A, Polyak K, et al. Incidence and functional

consequences of hMLH1 promoter hypermethylation in colo-

rectal carcinoma. Proc Natl Acad Sci USA. 1998;95:6870–5.

31. Kane MF, Loda M, Gaida GM, et al. Methylation of the hMLH1

promoter correlates with lack of expression of hMLH1 in spo-

radic colon tumors and mismatch repair-defective human tumor

cell lines. Cancer Res. 1997;57:808–11.

32. Lim SB, Jeong SY, Lee MR, et al. Prognostic significance of

microsatellite instability in sporadic colorectal cancer. Int JColorectal Dis. 2004;19:533–7.

33. Ribic CM, Sargent DJ, Moore MJ, et al. Tumor microsatellite-

instability status as a predictor of benefit from fluorouracil-based

adjuvant chemotherapy for colon cancer. N Engl J Med.2003;349:247–57.

34. Barnetson RA, Tenesa A, Farrington SM, et al. Identification and

survival of carriers of mutations in DNA mismatch-repair genes

in colon cancer. N Engl J Med. 2006;354:2751–63.

35. Lamberti C, Lundin S, Bogdanow M, et al. Microsatellite insta-

bility did not predict individual survival of unselected patients

with colorectal cancer. Int J Colorectal Dis. 2007;22:145–52.

36. Salahshor S, Kressner U, Fischer H, et al. Microsatellite insta-

bility in sporadic colorectal cancer is not an independent

prognostic factor. Br J Cancer. 1999;81:190–3.

37. Lanza G, Gafa R, Santini A, et al. Immunohistochemical test for

MLH1 and MSH2 expression predicts clinical outcome in stage II

and III colorectal cancer patients. J Clin Oncol. 2006;24:2359–

67.

38. Parc Y, Gueroult S, Mourra N, et al. Prognostic significance of

microsatellite instability determined by immunohistochemical

staining of MSH2 and MLH1 in sporadic T3N0M0 colon cancer.

Gut. 2004;53:371–5.

39. Malesci A, Laghi L, Bianchi P, et al. Reduced likelihood of

metastases in patients with microsatellite-unstable colorectal

cancer. Clin Cancer Res. 2007;13:3831–9.

40. Wright CM, Dent OF, Barker M, et al. Prognostic significance of

extensive microsatellite instability in sporadic clinicopathological

stage C colorectal cancer. Br J Surg. 2000;87:1197–202.


Absence of hMLH1 or hMSH2 Expression as a Stage-Dependent Prognostic Factor in Sporadic Colorectal...

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