Proliferation marker Ki-S11--a prognostic indicator for squamous cell carcinoma of the hypopharynx

As a potential prognostic factor, the proliferative activity of 131 squamous cell carcinomas (SCC) of the hypopharynx and 47 of their cervical lymph-node metastases was analyzed retrospectively by means of monoclonal antibody Ki-S11 immunostaining, which specifically detects the Ki-67 antigen on paraffin-embedded tissue. Median follow-up time was 37.6 months. Ki-S11 revealed distinctive patterns of proliferating cells related to the degree of differentiation. The proliferation fractions in the primaries and their lymph-node metastases did not differ significantly. Patients with high proliferating hypopharynx carcinomas (>45% labeled cells) had a significantly lower 5-year-survival rate (16%) than patients with low proliferating tumors, whose 5-year-survival rate was 30% (P=0.01). A statistically significant positive correlation was also observed between proliferative activity and lymph-node status (P=0.012). In conclusion, the proliferative activity as determined by means of Ki-S11 immunostaining is of prognostic value with respect to both survival and metastatic risk in SCC of the hypopharynx.