MIB 1 immunostaining in stage I squamous cervical carcinoma: relationship with natural killer cell activity

The aim of the study was to investigate the prognostic significance of estimating tumor cell proliferation in stage I cervical squamous carcinoma by analyzing MIB 1 immunostaining with respect to the lesion size, lymphatic spread, and clinical outcome. A possible relationship between MIB 1 index and natural killer activity was also discussed. The medical records of 34 patients with stage I squamous cervical carcinoma who had undergone primary radical surgery at the Institute of Gynecologic and Obstetrics, Ancona University, between 1988 and 1993, were recruited from our series of 57 consecutive cases and reviewed. Thirty-one patients were considered eligible for the study and evaluated for age, demographic characteristics, tumor histologic grade, tumor size, lymphatic spread, and adjuvant radiotherapy. The expression of primary tumor proliferation related to Ki67 antigen was immunohistochemically evaluated by monoclonal MIB 1 antibody (Immunotech, Marseille Cedex, France) on microwave oven-processed formalin-fixed paraffin-embedded tissue. The basal natural killer cell activity of peripheral blood lymphocytes was evaluated against K562 cell line and expressed in lytic units for each patient. The MIB 1 immunostaining was significantly related with tumor size (P = 0.001) and lymphatic spread (P = 0.009); in contrast, there was no relationship between grade of histologic differentiation and MIB 1 immunostaining. The Cox proportional hazards analysis showed a significant independent relationship between MIB 1 immunostaining and disease-free survival (P = 0.004). The analysis of natural cytotoxicity defined a significant inverse relationship between peripheral blood lymphocyte's natural killer activity and tumor MIB 1 immunostaining (r = -0.07, with P = 0.03). Our data defined the prognostic significance of tumor cell proliferation immunostaining, an interesting parameter correlated with the disease-free survival in locally advanced cervical carcinoma. The relationship between MIB 1 index and natural killer activity is interesting; natural cytotoxicity seems to be altered in the host with respect to the cervical carcinoma characteristics.