Ki-67 expression in the invasion front as an additional independent significant prognostic factor influencing reccurence in early stage cervical carcinomas.

Abstract

INTRODUCTION: The attempts to determine the prognostic significance of biological markers and their relation to human papillomavirus (HPV) infection in cervical cancer have yielded controversial results. AIMS: The aims of this retrospective study were to correlate alterations of cell proliferation, growth, differentiation and apoptosis regulatory proteins in early stage cervical carcinomas with HPV infection, histopathological and clinical parameters, and to estimate their prognostic significance. METHODS: Expression of Ki-67, p53, mdm-2, bcl-2, c-erbB-2, EGFR protein, as well as estrogen and progesterone receptors was evaluated by immunohistochemistry in operative specimens of 83 patients with early stage cervical carcinoma. The results were assessed semiquantitatively in the surface area, center and invasion front of each tumor as a percentage of the immunostained cells and/or intensity of immunostaining for each protein. The presence of HPV was assessed by conventional in situ hybridization (ISH) technique and catalyzed reporter deposition signal amplification ISH using mixed biotinylated probes to identify types 6/11, 16/18 and 31/33 or 31/33/51. RESULTS: In our case series 73 patients had a tumor limited to the uterine cervix less than 4 cm in diameter (pT1b1), while 10 patients had larger neoplasms belonging to pT1b2 category. Pelvic lymph node involvement was found in 20 patients. During the follow-up period (range, 65 -181, mean, 121 months) recurrences were observed in 9 patients. The 5, 10 and 15-year disease-free survival rate was 92.7%, 90.8% and 86.6%, respectively. Among the 18 variables pelvic lymph node involvement (P=0.0008), tumor diameter (P=0.035), depth of stromal invasion (P=0.029), histotype (P=0.0009), grade (P=0.056), HPV DNA presence (P=0.056), HPV type (P=0.043), as well as bcl-2 (P=0.035), mdm-2 (P=0.051), EGFR (P<0.0001), and Ki-67 (P=0.031) expression in the tumor’s invasion front were identified as important predictive indicators of recurrence in the univariate analysis. Independent significant prognostic factors for disease-free survival in multivariate analysis were the histotype, HPV DNA presence and Ki-67 expression. CONCLUSIONS: The invasive front of carcinomas proved to be the most important area for tumor prognosis. In addition to the detection of HPV presence and morphological parameters, Ki-67 evaluation could be used in selecting appropriate therapeutical approaches in patients with early stage cervical cancer.