Abstract :
Introduction: Bcl 2 is one of the unique proto-oncogene, localized to mitochondria & interfering with
apoptosis independent of promoting cell division. Bcl-2 is overexpressed mostly in SCLC and in a minority
of the NSCLC. Cyclin D1 is an important cell cycle regulatory protein which controls the cell cycle
transition from G1 to S phase.
Materials and Methods: Here, we studied immunohistochemical expression of Bcl 2 & Cyclin D1 in 40
lung cancer patients to evaluate the immunohistochemical expression of Bcl 2 & Cyclin D1 in primary lung
cancer, its expression with histological subtypes of lung cancer & to correlate the expression of Bcl 2 &
Cyclin D1 with the clinical stage of disease.
Results: The immunohistochemical expression of Bcl 2 & Cyclin D1 was studied in 40 cases of lung
cancer and was also correlated with the histological subtypes. Out of 40 cases of lung carcinoma, 21 cases
(52.5%) were positive and 16 cases (40%) were negative for Bcl 2. Among histological subtypes, Bcl 2
was significantly higher in patients with small cell carcinoma, (80%) followed by squamous cell carcinoma,
(78.57%). Out of 40 cases of lung carcinoma, 16 cases (40%) were positive and 21 cases (52.5%) were
negative for Cyclin D1. Among histological subtypes, expression of Cyclin D1 was significantly higher
in patients with adenocarcinoma, (52.38%) as compared to Squamous cell carcinoma (35.71%). The
immunohistochemical expression of Bcl 2 and Cyclin D1 was correlated with the clinical staging of lung
cancer. We observed higher Bcl 2 expression in stage 3 disease (81.82%) followed by stage 4 disease
(55%). Higher Cyclin D1 expression was seen in patients with stage 4 disease (80.00%). None of the stage
2 and stage 3 patients showed any expression with cyclin D1.
Conclusions: In our study, higher Bcl 2 expression was associated with small cell carcinoma of lung
and among non small cell carcinoma its expression was higher in squamous cell carcinoma. Cyclin D1
expression was observed mostly in adenocarcinoma cases. On correlating the expression of these markers
with clinical staging, we concluded that Bcl 2 is highly expressed in patients with stage 3 disease and
Cyclin D1 expression was mostly associated with stage 4 disease.
Keyword :
Bcl-2, Cyclin D1, Lung cancer, Immunohistochemistry, Clinical staging.