The prognostic value of Ki-67 antigen in non-Hodgkin lymphoma of Waldeyer ring and the nasal cavity.

BACKGROUND: A monoclonal antibody, Ki-67, recognizes an antigen expressed in all phases of the cell cycle, except G0, and can be used as a simple histologic marker of cell proliferation. To assess the prognostic value of the growth fraction in non-Hodgkin lymphoma of Waldeyer ring (W-NHL) and the nasal cavity (N-NHL), the authors applied Ki-67 immunostaining combined with image analysis on such lymphomas.

METHODS: The authors studied 29 patients (18 with W-NHL and 11 with N-NHL), applying Ki-67 to frozen sections. The number of Ki-67-positive cells in a unit area (0.044 mm2), as an indicator of proliferative activity, and the mean area per Ki-67-positive cell (microns2), as an indicator of DNA content, were measured by the image processing system.

RESULTS: High-grade lymphomas showed a significantly larger number of Ki-67-positive cells than intermediate-grade lymphomas (102.5 +/- 21.6 in high-grade and 46.8 +/- 8.92 in intermediate-grade lymphomas, P = 0.03), even when analyzed separately by immunophenotypes. A large mean area per Ki-67-positive cell was associated significantly with a T-cell phenotype (36.3 +/- 7.69 microns2 in T-cell lymphomas and 19.4 +/- 2.33 microns2 in B-cell lymphomas, P = 0.034) and an unfavorable clinical outcome. High proliferative activity, defined as nuclear Ki-67 expression in 2000 or more B-cell lymphoma cells and 1000 or more T-cell lymphoma cells in a 1-mm2 area, was found to be a strong predictor of poor survival among these patients (P = 0.048 and P = 0.009, respectively).

CONCLUSIONS: Ki-67 immunostaining, combined with image analysis, is a novel method for determining a tumor proliferative index that provides useful clinical data regarding head and neck lymphomas.