Jennie BellCMGS/ACC Spring meeting

14th April 2010

Cancer cells acquire the capacity for autonomous and dysregulated proliferation•Uncontrolled production of growth factors

•Enhanced expression of growth factor receptors↳Proliferation of cancer cells↳Induction of angiogenesis↳Metastasis

Lung cancer cell

KRAS

C-KIT

EGFR

EGFR is a transmembrane receptor belonging to a family of 4 related proteins

The majority of human epithelial cancers are marked by activation of growth factors and receptors of the epidermal growth factor receptor family

KRAS is a gene in the EGFR signaling pathway

Activating mutations impair GTPase activity resulting in constitutive activation

Up to 30% of all human tumours contain a KRAS mutation

Most commonly observed in lung, colon and pancreatic cancer and haematopoietic neoplasm

http://www.kras-info.com/

c-KIT is a proto-oncogene and a transmembrane receptor

Ligand binding activates intracellular tyrosine kinase domain

PDGFRa is homologous to KIT and functions in a parallel pathway.

Both genes can be mutated in GIST Gastrointestinal stromal tumours.

EGFR was the first growth factor receptor proposed as a target for cancer therapy.

Development of EGFR antagonists for treatment of metastatic epithelial cancers:• Non-small-cell lung cancer (NSCLC)• Squamous cell carcinoma of head and neck• Colorectal cancer• Pancreatic cancer

EGFR inhibitors approved for cancer treatment:

Erlotinib

Gefitinib

Cetuximab

Panitumumab

Gefitinib, a small molecule tyrosine kinase inhibitor, is a targeted therapy for the treatment of patients with non-small cell lung cancer

The drug binds to the EGFR TK domain with high specificity and affinity resulting in highly effective inhibition of the aberrant signalling pathways.

Imatinib is a synthetic tyrosine kinase inhibitor (Glivec, Novartis Pharmaceuticals UK) successfully used in the treatment of CML

Imatinib can block the activated receptor tyrosine kinase activity of c-kit

Targeted therapeutic approach in GIST.

Not all patients respond in the same way to drug treatment

The presence or absence of a mutation can influence response

The presence of different somatic mutations within each gene can affect the action of the drug at the cellular level

Clinical trials have shown that patients with certain EGFR mutations derive significant benefit from gefitinib treatment while patients without these mutations gain more benefit from standard chemotherapy

Mutations are found in four exons of the EGFR gene (exons 18 to 21).

Deletions in exon 19 and a point mutation in exon 21 (L858R) account for around 90% of all activating mutations

As Gefitinib has been shown to benefit patients with particular somatic sequence changes

Essential to identify specific sequence changes in individual patients

Match sequence variants with specific patient treatment

GIST patients with a somatic mutation generally have a higher response to treatment than those that do not.

Exon 11 most commonly mutated in (67% of cases) • Mutations in exon 11 generally respond to treatment with

Imatinib better than mutations in other exons. Exon 9 mutations are less common (17% of cases)

• Exon 9 mutations have a lower response rate to Imatinib therapy vs exon 11 mutations (but a better response rate to Imatinib than c-kit "wild-type" GIST)

There has been a recent paradigm shift in cancer patient treatment

Broad-spectrum cytotoxic therapy molecular targeted treatment

The presence of a sequence variant within one of these genes (EGFR, c-Kit, KRAS) can determine a patient’s treatment.

A patient presents with lung cancer A biopsy is taken A diagnosis of NSCLC should be confirmed

by a Consultant Histopathologist Subsequent molecular analysis of the

tumour sample is required Identifying patients with an EGFR mutation

is a critical part of the patient care pathway Appropriate treatment discussion with

patient

Dr Philippe TanièreConsultant HistopathologistUHB

Brendan O’Sullivan/Frances HughesBMS, UHBJennie Bell/Dr Fiona MacdonaldConsultant Clinical Scientists, BWH

http://www.egfr-info.com/EGFR-exon

Department of Cellular Pathology UHB

West Midlands Regional Genetics BWH

Partnership established in 2002

Department of Cellular Pathology, University Hospital Birmingham and West Midlands Regional Genetics Laboratory

Tumour studies in colon cancer (MSI and IHC in Lynch syndrome/HNPCC)

KIT and PDGFRa analysis for GIST • Sequencing exons 9, 11, 13, 17 c-kit and exons 10, 12, 14, 18

PDGFRa

KRAS analysis for lung and colon cancer• Pyrosequencing exon 2 KRAS

EGFR for lung cancer• Analysis of exons 18 to 21 (RQ-PCR, sequencing)

All molecular work is performed within the Regional Genetics Laboratory

A basic report is issued giving details of any sequence variants identified (or not)

The results are integrated into an overall patient summary by Consultant Histopathologist

* Samples reported 1st Jan to 31st March 2010

* Samples reported 1st Jan to 31st March 2010

Validation

Service validation complete Problem with availability of DxS kit Currently using direct sequencing Reports will be issued from 1st April 2010

BRAF analysis in colorectal cancer • Pyrosequencing based assay

BRAF and KIT in melanoma• KIT mutated in non-skin melanomas• BRAF mutated in sun exposed areas

MGMT methylation in gliomas and endocrine tumours • predictive to alkylant based chemotherapy

ERCC1 expression • RNA based test on paraffin sections• Predictive marker to response to platinum based chemotherapy

(lung, pancreas, stomach and colon)

Management of results for patients referred with cancer is co-ordinated by Consultant Histopathologist

Equipment and molecular expertise is provided by the Genetics Service

Molecular testing is performed to accredited standards

More drug targets

Improved drug treatments

Further expansion of molecular pathology services is anticipated

Supported by strong cross-discipline collaboration

Molecular Laboratory Staff

Dr Fiona Macdonald

jenny.bell@bwhct.nhs.uk

Brendan O’Sullivan Frances Hughes Dr Philippe Tanière

phillipe.taniere@uhb.nhs.uk