This tumor suppressor p53 gene plays an important role in the onset of SCLC development by enabling the invasion, metastasis, proliferation and cell survival of malignant cells [53], Apaf1 is involved in apoptosome formation and its low expression is observed in aggressive tumors [54] and occurs in lung tumors such as NSCLC [55]. This evidence concerns the gene TP53 and small cell lung carcinoma.