AIMS: To evaluate the
prognostic value of
immunohistochemical expression of
Bcl-2 in
colon cancers. PATIENTS AND METHODS: Two hundred and twenty-six resected and paraffin-embedded
colon carcinomas were analysed by
immunostaining using
monoclonal antibodies for
Bcl-2. We evaluated whether the
Bcl-2 staining patterns, semi-quantitatively assessed, could be
correlated with the pTNM stage, size and
tumour circumference, differentiation, appearance, vascular invasion, perineural invasion,
colloid component, margins, involvement of adjacent structures, stromal appearance,
flow cytometry and the
S-phase. RESULTS: Eighty patients (36%) were considered
Bcl-2 positive. The extent of
Bcl-2 expression by
tumour cells decreased significantly
with respect to increasing
tumour size (P=0.042), the extension of parietal invasion pT (P=0.007), the invasive nature of the
tumour (P=0.024), and extent of the circumference (P=0.024). In a
multivariate analysis,
Bcl-2 expression does not appear as an independent prognosis factor in the overall population as in the 166 patients with optimal resection. Of the 59 stage II patients, using
univariate analysis,
Bcl-2 appears to be predictive of relapse-free survival (P=0.025) but not of overall survival (P=0.09). CONCLUSION: The loss of
Bcl-2 expression appears to be
correlated with increase in number of relapses in the stage II
colon cancers and could be a potential useful additional histo-prognostic marker in therapy
decision making.
Bcl-2 immunodetection seems to be associated with slower local
tumour growth.
