Expression of p16INK4 and Rb Genes in Cervical Neoplasm

The molecular events surrounding the pathogenesis of human cervical cancer remain to be defined to a significant extent. The current study investigates the expression of two putative tumor suppressor genes p16 and Rb in cervical neoplasm. Tissue was collected from 16 cervical intraepithelial neoplasia (CIN) patients and 91 cervical cancer patients prior to definitive treatment. Immunohistochemical staining for p16 and Rb protein was performed in these cases to determine the relationship between the expression of these two genes in premalignant and malignant neoplasias of the cervix. Eight (50%) CIN and 9 (10%) of cervical carcinoma cases lacked p16 expression, while 4 CIN (25%) and 34 carcinoma (37%) cases did not display Rb expression. The prevalence of negative p16 expression in CIN was significantly higher than in cervical carcinoma (p < .01). The prevalence of negative Rb expression was higher than was negative p16 expression in cervical carcinoma (p < .01). Alterations of p16 and Rb are relatively exclusive in both CIN and carcinoma (p < .01). No statistically significant relationship was found between either p16 or Rb expression and tumor cell type, histological grade, or clinical stage in cervical carcinoma. Deficiency of either p16 or Rb protein appears to be contributory to oncogenesis of cervical neoplasm in different subgroups of patients. Whether negative p16 expression commonly is involved in the pathogenesis of CIN must be confirmed.