Bax, Bcl-2 and C-kit Expression in Non-small-cell Lung Cancer and Their Effects on Prognosis

In non-small-cell lung cancer (NSCLC), stage of the disease is still the most important prognostic factor. Other than stage, many biological markers and many other prognostic factors are studied to define their effects on prognosis of lung cancer. In this study, we aimed to evaluate the expressions of Bax and bcl-2 genes which are important in apoptosis and c-kit, which is a tyrosine kinase transmembrane receptor, as well as searched their response to treatment modalities and effects on survival. Sixty-nine NSCLC cases' pathological samples were stained with specific Bax, bcl-2 and c-kit dyes by immunohistochemical (IHC) methods. IHC evaluation was done by the semichantitative method according to the distribution and intensity of the staining. Twelve of 69 cases (17.4%) were stage I, 28 (40.5%) were stage II, 17 were (24.6%) stage IIIA, nine cases were (13.1%) stage IIIB and three cases (4.4%) were stage IV patients. Their histological subtypes were as follows: of 69 cases, 36 (52.2%) were squamous cell carcinoma, 28 (40.6%) were adenocarcinoma, five (7.2%) were adenosquamous cell carcinoma (two patients) and large-cell carcinoma (three patients). The positive immunostaining rates for Bax and bcl-2 in whole group, squamous cell carcinoma and adenocarcinoma groups were 40.6%/36.2%, 55.6/69.4% and 25.0/0.0%, respectively. The positive immune staining rates for c-kit in whole group, squamous cell carcinoma and adenocarcinoma groups were 7.2, 5.6 and 7.1%, respectively. We didn't find any correlation with Bax, bcl-2 and c-kit expressions and clinicopathological parameters such as age, tumour size, lymph node involvement, smoking, stage of the disease, response to radiotherapy and chemotherapy. Results are interpreted according to survival; bax and bcl-2 expressions were not so effective both in whole group and histologically subgrouped patients. C-kit expression was also found not related with survival in whole group whereas found as a bad prognostic factor in patients with squamous cell carcinoma. These findings could indicate that the expression of apoptotic pathway markers and c-kit may have a role in the prognosis of early stage NSCLC, especially with squamous cell carcinoma subtype.