BCL-2 EXPRESSION IN ENDOMETRIAL CARCINOMAIN RELATION TO DIFFERENT HISTOPATHOLOGIC

PROGNOSTIC FACTORS

251

Journal of Experimental Medical & Surgical Research

Cercetãri Experimentale & Medico-Chirurgicale

Year XVII · Nr.4/2010 · Pag.251 - 254E x p e r i m e n t a l

M e d i c a l S u r g i c a l

R E S E A R C H

J O U R N A L o f

Correspondence to: G Guset, MD, Obstetrics and Gynecology Department, Clinical Hospital, Arad, 3 Cornel Radu Street,310329 Arad, Romania; Phone +40744607047, E-mail gusetgrig@yahoo.com

SUMMARY:The bcl-2 protooncogene inhibits programmed cell death (apoptosis) and over-expression of bcl-2 might play a role in carcinogenesis and malignant progression of endometrialcarcinoma.. The aim of this study was to determine bcl-2 immunohistochemical expressionin patients with endometrial carcinoma and to correlate it with different histologicalparameters including histological type, tumor grade, depth of myometrial invasion,lymph-node involvement and stage. Fifty-four patients with endometrial carcinoma whowere treated by total abdominal hysterectomy and bilateral salpingo-oophorectomy wereassessed. The immunohistological staining was performed on formalin-fixedparaffin-embedded tissue, and haematoxylin and eosin-stained sections were used toevaluated the conventional prognostic markers. Bcl-2 expression was positive in 63.41% ofendometrioid carcinomas and in 53.84% of non-endometrioid carcinoma (p = 0.5374 NS).Statistically significant correlation was found between the surgical staging, depth ofmyometrial invasion, lymph node involvement , tumor grade and the bcl-2 expression ( p <0.001, p = 0.0019, p = 0.0138 and p = 0.0136 respectively).Key-words: bcl-2, endometrial carcinoma, prognosis

REZUMAT: Protooncogena bcl-2 inhibã moartea celularã programatã (apoptoza), supraexpresia bcl-2putând juca un rol în carcinogeneza ºi evoluþia carcinomului endometrial. Scopul acestuistudiu este de a determina expresia imunohistochimicã a anticorpului bcl-2 la paciente cucarcinom endometrial ºi corelarea acesteia cu diferiþi parametri histologici incluzând tipulhistologic, gradul de diferenþiere, adâncimea invaziei miometriale, statusul limfonodulilor ºistadiul bolii. Au fost luate în studiu cincizeci ºi patru de paciente cu carcinom endometrialtratate prin histerectomie totalã cu anexectomie bilateralã. Imunocolorarea s-a realizat peþesuturi fixate în formaldehidã, incluse la parafinã, iar markerii convenþionali de prognosticau fost evaluaþi pe secþiuni colorate cu hematoxilinã- eozinã. Expresia bcl-2 a fost pozitivã în63.41% din carcinoamele endometrioide ºi în 53.84% din carcinoamele non-endometrioide(p=0.5374 NS). Între expresia bcl-2 ºi stadiul bolii, adâncimea invaziei miometriale,statusul limfonodulilor ºi gradul de diferenþiere al tumorii s-a obþinut o corelaþiesemnificativã statistic ( p < 0.001, respectiv p = 0.0019, p = 0.0138 ºi p = 0.0136 ).Cuvinte-cheie: bcl-2, carcinom endometrial, prognostic

G. Guºet1, S. Costi2, E. Lazãr3,A. Dema3, C. Lãzureanu3, C. Vernic4, L. Pãiuºan5

Received for publication: 04.05.2010

Revised: 12.10.2010

1. - Obstetrics and Gynecology Department, Clinical Hospital, Arad2 - Service of Pathology, Emergency Clinical Hospital, Timisoara3 - Department of Pathology4 - Deparment of Medical Informatics and Biostatistics, „Victor Babes” University of Medicine and Pharmacy, Timisoara5 - Department of Pathology, „Vasile Goldis” Western University, Arad

INTRODUCTION

The bcl-2 gene encodes a protein of 25-26 kDa (Bcl-2),

which is located in the mitochondrial membrane,

endoplasmic reticulum and nuclear membrane.(1)

In the endometrium, bcl-2 expression assessed by

immunohistochemistry varies during the menstrual cycle

and is highly expressed in the proliferative phase, with

downregulation during the secretory phase (2). Many

studies support the concept that bcl-2 protein expression

persists at high levels in simple hyperplasia but

progressively diminishes in atypical hyperplasia and with

deacreasing differentiation in invazive endometrial

adenocarcinoma (3,4,5,6,7,8,9).

The aim of this study was to determine bcl-2

immunohistochemical expression in patients who have

been surgically treated for endometrial carcinoma, and to

correlate it with conventional histological markers.

Conventional histological and prognostic markers used to

determine the clinical course of endometrial carcinoma

include histological type, tumor grade, depth of

myometrial invasion, lymph-node involvement and stage.

MATERIALS AND METHODS

In order to investigate bcl-2 expression in endometrial

neoplasia, a total of fifty-four endometrial carcinoma

cases surgically resected at Obstetrics and Gynecology

Department of Clinical Hospital Arad were examened.

The mean age of patients was 57 years with a minimum

of 38 and maximum of 81 years. All patients had been

treated surgically with total abdominal hysterectomy and

bilateral salpingo-oophorectomy. Oh these, 25 patients

were stage I, and 29 patients were stage II and III. N

staging was based on pre-operative lymphangiography

or pelvic and abdominal tomography (CT) scan. The

cases investigated comprised 24 grade 1 (G1), 21 grade

2 (G2), and 9 grade 3 (G3) endometrial carcinomas

(Table I). Histologic typing of the endometrial tumours,

tumor grade and depth of myometrial invasion (< ½ vs

> ½ ) were evaluated based on the criteria of the World

Health Organization.

Tissue samples were fixed in 10% formalin and

embedded in paraffin wax for routine histopathology.

Immunohistochemical Analysis: The deparaffinized

tissue sections were submitted to routine

immunohistochemical analysis using as positive controls

for bcl-2 expression lymph nodes. The antibody used was

mouse monoclonal anti-human bcl-2 antibody (clone

124, Dako) through LSAB 2 detection system. A variable

intensity of bcl-2 immunoreactivity was observed with

cytoplasmic brown staining; the visualization system

used diaminobenzidine tetrahydrochloride (DAB, Dako).

Statistical Analysis: The correlation between bcl-2

expression and histopathologic markers were analyzed

using Chi-square test. A p value less than 0.05 was

considered significant.

RESULTS

On the basis of the percentages of bcl-2

immunopositive cells in the endometrial carcinomas, the

lesion were included into four categories as follows:

n 0 = negative: no or fewer than 5% positive cells;

n 1+ = positive immunoreaction in 5-20% of tumor

cells;

n 2+ = positive immunoreaction in 30-50% of tumor

cells;

n 3+ = positive immunoreaction in more than 50% of

tumor cells;

A variable intensity of a bcl-2 immunoreactivity (weak,

moderate or strong) and a heterogenous distribution of

cytoplasmic staining were observed.

The correlations of bcl-2 expression with histological

parameters are listed in Table II. In our study , we

detected cytoplasmic bcl-2 expression in 26

endometrioid carcinomas (63.41%) and 7 non-

endometrioid carcinomas (53.84%); differences were not

statistically significant (p = 0.537467 NS). Statistically

significant correlation was found between the tumor

differentiation grade and bcl-2 expression: 21 (87.50%) of

G1 endometrial carcinoma were bcl-2 positive, while

bcl-2 expression was positive in only 12 (57.14 %) of G2

and G3 cases (p = 0.013676 S). Statistically significant

correlation was found between depth of myometrial

invasion and bcl-2 expression (p = 0.001916) and

between surgical staging and bcl-2 expression (p <

0.001 ES). By comparing bcl-2 expression and the status

of limph nodes we obtained positive bcl-2 reactions in

67.34% of cases without metastasis while the lymph

nodes with metastasis were not positive (p = 0.013852

S).

DISCUSSION

Several studies are focused on the genetic and

molecular changes that are observed in endometrial

carcinomas.

The fact that bcl-2 expression was correlated with

favorable clinicopathological markers in our study is in

line with other studies (Saegusa et al, Saegusa et

Okayasu, Erlich et al, Creasman et al, Sivridis et al) that

demonstrated a close association between bcl-2 and

252

progesterone receptor immunoreactivity, since it is

widely accepted that the later is also linked to a favorable

outcome (10,11,12,13,14). In many studies (Geisler et al,

Taskin et al, Saegusa et al, Coppola et al, Yamauchi et al))

bcl-2 positivity has been directly correlated with a

favorable clinical outcome and good histopathologic

prognostic factors i.e. well-differentiated endometrioid

tumors, superficial myometrial invasion and early staging

(5, 9, 11,15,16). Similar results have been observed for

other tumors, including breast, lung and thyroid

carcinomas (17,18,19).

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CharacteristicsNumber of

patients (%)Bcl-2 positive (%) Bcl-2 negative (%)

Histological type

Endometrioid

Non-endometrioid

54 (100)

41 (75.92)

13 (24.08)

33 (61.11)

26 (63.41)

7 (53.84)

21 (38.89)

15 (36.59)

6 (46.16)

Tumor grade

G1

G2

G3

24 (44.45)

21 (38.88)

9 (16.67)

21 (87.50)

12 (57.14)

0 (0.0)

3 (12.50)

9 (42.86)

9 (100)

Table 2. Correlation between bcl-2 expression and the histopathological prognostic markers of patients with endometrialcarcinoma.

Markers Number of patients %

Histological type

Endometrioid

Non-endometrioid

41

13

75.92

24.08

Tumor grade

G1

G2

G3

24

21

9

44.45

38.88

16.67

Table 1. Histopathological markers of endometrial carcinomas.

Several other studies do not reveal any correlation

between bcl-2 expression and known prognostic factors.

Giatromanolaki et al (20) performed a study on 133

patients with endometrial carcinoma and did not fiind any

relationship between bcl-2 and tumor grade, depth of

myometrial invasion and lymphovascular invasion.

Sakuragi et al (8) did not demonstrate any significant

differences in bcl-2 expression when lymph node

involvement and tumor grade were analyzed, but this

expression was lincked inversely proportional to

myometrial invasion (p=0.025). Kounelis et al (21)

performed a study on 61 patients and did not obtained

any significant difference between bcl-2 expression and

histopathological type, tumor grade and staging. Appel et

al (22) studied 48 Brazilian patients with a histological

diagnosis of endometrial carcinoma and did not

demonstrate any correlation between bcl-2 expression

and age, histological type,tumor grade, depth of

myometrial invasion and survival.

CONCLUSIONS

In conclusion, the present study provided strong

evidence that, in endometrial carcinoma, bcl-2

expression is associated with favorable prognostic

factors and may play important roles in tumor

progression from early to advanced stages.

254

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