Projects / Programmes
Somatic mutations in genes responsible for melanoma development and clinical disease prognosis
| Code |
Science |
Field |
Subfield |
| 3.04.00 |
Medical sciences |
Oncology |
|
| Code |
Science |
Field |
| B200 |
Biomedical sciences |
Cytology, oncology, cancerology |
| Code |
Science |
Field |
| 3.02 |
Medical and Health Sciences |
Clinical medicine |
melanoma, somatic mutation, prognosis
Researchers (14)
Organisations (2)
Abstract
Cutaneous melanoma represents less than 5% of skin cancers but it causes more than 80% of all skin cancer related deaths. Additionally, unlike most other cancers melanoma is frequent among young and middle aged adults and as such it is one of the major cancer related causes of lost productive years.
Somatic mutations in different regulatory genes are responsible for melanoma initiation, promotion and progression. One of the earliest and probably obligatory event in melanoma pathogenesis is a constitutive activation of the RAS-RAF-MEK-ERK pathway by which melanocytes acquire a proliferation capability. The next crucial step in melanoma cancerogenesis is disruption of a senescence barier. In this respect, the first line of defense may be the INK4A (p16)-CDK4-RB pathway, which is activated in melanocytes in response to mutant B-RAF. A second line of defense may involve ARF and TP53 which are both implicated in cellular senescence and are mutated in most melanomas. A late event in melanoma progression is activation of the PI3K-AKT pathway via PTEN, C-KIT, N-RAS or other genetic events by which melanoma cells acquire metastatic capabilities.
Information about genetic and epigenetic changes of primary melanomas and their metastases can provide us with important prognostic information and at the same time give us the opportunity of using different targeted therapies according to the detected specific changes.
The aims of our study are:
· To detect mutations in genes of two pathways involved in melanoma pathogenesis (C-KIT, N-RAS, B-RAF, MEK, PI3K, AKT and MITF) or their regulation (ATM and CCND1) in primary tumors and/or lymph node metastases of patients with follow-up of at least 3 years
· To compare the results of gene analysis with clinical prognostic information used in the current TNM staging system (Breslow thickness, ulceration, micro/macro lymph node metastases)
· To compare frequency of gene mutations in primary tumors and or/lymph node metastases in patients with the same clinical prognostic information but different course of disease (patients with relapses versus patients without relapses)
We will analyze 5 different groups of patients with melanoma from a prospective melanoma database of the Institute of Oncology, Ljubljana, Slovenia treated in the period from 2001-2007:
1. 70-100 patients with localized melanoma (stage I and II)
2. 70-100 patients with clinically occult lymph node metastases (stage IIIA)
3. 70-100 patients with metachronuosly clinically detected lymph node metastases (stage IIIB)
4. 50 patients with synchronously clinically detected lymph node metastases (stage IIIB)
5. 40 patients with lymph node metastases and unknown primary
All patients are routinely followed-up at the Institute in outpatient department.
DNA will be extracted from paraffin-embedded tissue and the allelic discrimination method will be used for determination of mutations in the selected genes. Direct sequencing will be used for conformation of the results. Additionally, the number of copies of the gene of interest will be determinate.
Clinical data (gender, age, pathomorphological characteristics of primary tumor and metastases, disease free and overall survival) will be collected from the prospective melanoma database of the Institute of Oncology from the period 2001-2007.
Survival curves will be calculated by Kaplan-Meier's method. Univariate and multivariate analyses using log-rank test and Cox's regression model will be used for the assessment of the factors associated with OS and for comparison of OS between different subgroups of patients. Quantitative variables will be compared using Student or the Wilcoxon test and categorical variables using Chi-square test.
Significance for science
Results of the clinical part of the research project confirmed and to certain extent explained the heterogenity of patients with melanoma. According to our results tumor burden is the most important part in the disease progression. In patients with small metastases the time of lymphadenectomy is crucial for the prognosis. Patients with completion lymphadenectomy after a positive sentinel lymph node biopsy have a 20% prognostic advantage. These results are in line with the theory of secondary metastases – from regional lymph nodes to systemic sites. In the molecular part of the project we came to a point where a methodological problems at the moment preclude final conclusions.
Significance for the country
Conclusion that patients with immediate lymphadenectomy have a better prognosis in comparison to patients with a delay lymphadenectomy caused a change in treatment guidelines. In all patients with melanoma ticker than 1 mm a sentinel lymph node biopsy is recomended and in the case of a positive result a completion lymphadenectomy is performed. By this approach about 20% more patients with regional metastases are cured. Since these are patients in the most productive years (30-60 years old) this represents a major step forward for a whole society.
Most important scientific results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
