Determination of EGFR, KRAS, BRAF, PIK3CA, HER2 and NRAS gene mutations in parafin block sections from patients diagnosed with non-small cell lung cancer

Nowadays, cancer is a disease with the highest mortality rate after cardiovascular diseases. The leading cause of cancer deaths is lung cancer and %85 of this type of cancer forms of Non-Small Cell Lung Cancer (NSCLC). The majority of patients can be detected in advanced stages because of the silent course of lung cancer. In advanced stages surgical intervention options are reduced as well as chemotherapy and radiotherapy fail is extremely low, furthermore cases which gives different answers despite the implementation of same chemotherapeutic drugs is forced the clinician in terms of treatment options. Improvements have been recorded in cancer treatment with the identification of genetic changes in tumor tissue and with the use of repressor molecule against onco-proteins resulting from these changes in recent years. The identification of genetic changes in cases and the generation of special personalized treatment have become extremely important. Diagnosis and treatment of lung cancer in our country are organized on the basis of Western society. Determining of genetic changes, detecting of ratio and revealing the correlations in Turkey's society will guide clinicians in treatment as it would be important in determining the priorities in diagnosis. In our study, we aimed to determine EGFR, KRAS, BRAF, PIK3CA, HER2 and NRAS gene mutations as well as the ratio and correlation of these mutations in sections which were taken from the paraffin blocks of tumor of patients with NSCLC. DNA was isolated from paraffin block sections of patients with NSCLC by use of commercial "AmoyDx FFPE DNA Kit". Mutations were determined using AmoyDx commercial mutation kit with Cobas z (Roche) Real Time PCR instrument. Total of 80 patients with a diagnosis of NSCLC were included in this study. Cases were investigated for Epidermal Growth Factor Receptor (EGFR), V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS), v-Raf murine sarcoma viral oncogene homolog B (BRAF), phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA), human epidermal growth factor receptor 2 (HER2) mutations. In 46,2% of patients had at least one mutation. Mutations in EGFR, KRAS, BRAF, PIK3CA, HER2 ve NRAS genes were detected as 7(8,7%), 23(28,7%), 1(1,2%), 6(7,5%), 0(%), 1(1,2%) respectively, but no mutation was found in HER2 gene. In addition, mutations in KRAS and PIK3CA genes were determined in 1,2% of cases. These results showed that Turkish people has similarity in terms of mutations in Caucasian people. Only mutations in PIK3CA gene were detected over given result. We think that mutations in PIK3CA gene must be well considered in diagnosis and treatment of NSCLC. Also, no mutation was found in 43(53,7%) of cases. There is a need to investigate molecular factors in these cases which stimulate tumor development.