Is Nothingham Prognostic Index correlated with apoptosis and p53 expression in infiltrating ductal carcinoma of the breast?

The role of p53 as a prognostic factor is not clear. P53 named as "guardian of the genome" plays an important role in many intracellular regulatory systems, one of which is apoptosis, having an impact on tumor kinetics. A retrospective study was undertaken to assess the relationship of the Nothingham Prognostic Index (NPI) to p53 expression and apoptotic cell counts. To conduct the study, 160 successive cases of infiltrating ductal carcinoma of the breast were included. P53 was assessed on AP-AAP stained sections. Apoptotic cell counting (ACC) was done on the HE stained routine sections in 10 HPFs. Clinical data were derived from the hospital files. Apoptotic cell counts were higher in the p53 positive group but the difference was not significant (p=0.079). P53 positivity was found to be related to the disease-free survival (DFS) (p=0.008). NPI was significantly higher in apoptotic cell containing group (p=0.006). There was a positive linear correlation between ACC and NPI scores (p=0.004). This correlation was not present between apoptosis and disease free survival. P53 expression was found to be related with DFS but not with the NPI which is a score composed of the best prognostic indicators known today. In contrast to this, ACC was found to be closely and linearly associated to the known prognostic factors. This may suggest that the apoptotic cell counts done on routine sections may be used as a part of prognosis assessment in infiltrating ductal carcinoma.