A multiple marker analysis of apoptosis-associated protein expression in non-small cell lung cancer in a Chinese population

Abstract

A failure to undergo apoptosis is widely thought to be an important event in cancer formation and progression. Although there have been many studies in vitro that provide evidence for this suggestion, the roles of apoptosis-associated proteins in cancer tissues in vivo are not as yet fully understood. Moreover, multiple marker analyses of apoptosis-associated protein expression in non-small cell lung cancer (NSCLC) tissues are scarce. In the present study, we investigate the expression of a group of apoptosis-associated proteins including bcl-2, caspase-3, fas, fas ligand (fasL) and survivin, and its clinical significance in NSCLC tissues using immunohistochemistry (IHC). Bcl-2 staining in cancer tissue cells was found in cytoplasm and the positive rate was 38.2% (29/76). Caspase-3 staining was mainly seen in cytoplasm of cancer tissue cells (53.9% [41/76]) with a few cases of nuclear staining (6.6% [5/76]). Fas staining was seen in cytomembrane (15.8% [12/76]) and cytoplasm (42.1% [32/76]) of cancer tissue cells. Likewise, fasL also showed staining in cytoplasm (55.3% [42/76]) and cytomembrane (44.7% [34/76]) of cancer tissue cells. Survivin staining was seen in cytoplasm but not nuclear of cancer tissue cells and the positive rate was 48.7% (37/76). Higher cytoplasm expression of bcl-2 was associated with large tumor size (≥ 3 cm) in NSCLC (p < 0.05). Decreased cytoplasm expression of fas was associated with poor grade in NSCLC (p < 0.05). A negative correlation was found between bcl-2 and cytoplasm caspase-3 expression in NSCLC (p < 0.001). No separate expression of the apoptosis-associated proteins in NSCLC was linked to overall survival of patients (p > 0.05). Multiple marker analyses revealed caspase-3+/cytomembrane fasL- to be linked to better survival of patients with NSCLC (p < 0.05). These results indicate that apoptosis- -associated proteins may impact a variety of clinicopathological features of NSCLC and may co-operatively influence the prognosis of patients with this malignant tumor.