Clinical role of Bcl-2, Bax, or p53 overexpression in peripheral T-cell lymphomas

Apoptosis pathways are known to be involved in the pathogenesis of peripheral T-cell lymphomas (PTCLs). As such, the current study attempted to investigate the overexpression of Bcl-2, Bax, or p53 with respect to the progression of PTCL. Paraffin-embedded specimens from 74 patients were analyzed immunohistochemically for Bcl-2, Bax, or p53 overexpression including PTCL-unspecified (n=45), extranodal natural killer cell/T-cell lymphoma (n=10), angioimmunoblastic T-cell lymphoma (n=7), anaplastic large cell lymphoma (n=7), and cutaneous T-cell lymphoma (n=5). The Bcl-2 overexpression was exhibited in 33 (45%), Bax, 17 (23%), and p53, 33 patients (45%). Bcl-2 overexpression was strongly associated with advanced stage (p=0.021) and higher international prognostic indices (IPI) (p=0.038). Bcl-2(+)/p53(+) group was found to be associated with advanced stage (p=0.008) and higher IPI (p=0.001), compared with the other groups. The independent expression of Bcl-2 or p53 was not correlated with survival. Meanwhile, when confined to Bcl-2 over-expressing groups, p53 overexpression was significantly associated with poor survival (p=0.05), as the 3-year OS rate was 82.5% for Bcl-2(+)/p53- cases, yet only 32.9% for Bcl-2(+)/p53(+) cases. Multivariate analyses for OS found the Bcl-2/p53 co-expression (p=0.004) as independent prognostic factor, together with advanced stage (p < 0.001) and higher prognostic index for PTCL (p=0.008). Bcl-2 overexpression seemed to correlate with the progression of PTCL interacting with a p53-dependent pathway.