Apoptosis occurs independently of bcl-2 and p53 over-expression in non-small cell lung carcinoma.
Certain oncogenes and tumour suppressor genes are known to modulate apoptosis. To investigate whether overexpressed bcl-2 and abnormally stabilized p53 are associated with reduced apoptosis in paraffin sections of non-small cell lung carcinoma, apoptotic, mitotic, and Ki-67 labelling indices were determined and correlated with bcl-2 and p53 immunoreactivity in 54 squamous cell carcinomas and 22 adenocarcinomas. Nineteen squamous cell carcinomas (35.2%) showed over-expression of bcl-2, but all 22 adenocarcinomas were bcl-2 negative. Thirty-seven squamous cell carcinomas (68.5%) and 13 adenocarcinomas (59.1%) showed p53 over-expression. Apoptotic tumour cells were identified among p53 positive and bcl-2 positive tumour cells. There was a significant linear correlation between apoptotic indices and mitotic indices. bcl-2 over-expression and p53 over-expression were not associated with attenuated apoptosis, or altered mitotic or Ki-67 labelling indices in either tumour type. Neither bcl-2 nor p53 was of prognostic significance. These results suggest that apoptosis in non-small cell lung carcinoma occurs independently, and is not modulated primarily by, bcl-2 or p53. It is likely that the effects on apoptosis of bcl-2 and p53 are countered by those of other oncogene products and/or additional factors that regulate apoptosis in vivo.
O'Neill
A J
AJ
Department of Histopathology, St James's Hospital, Dublin, Ireland.
Staunton
M J
MJ
Gaffney
E F
EF
D000230:Adenocarcinoma / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism*; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis* / Q000096:biosynthesis*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000096:biosynthesis*
D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53