Over-expression of Ki-67 as a predictor of lymph node metastasis in penile cancer patients

Abstract

Introduction: Penile cancer is a moderately common malignancy in developing countries. Metastasis to regional lymph nodes is an essential factor in a patient’s prognosis, as its occurrence predicts poor patient prognosis. As micro-metastasis occurs in more than 25% of cases, the need for more accessible diagnostic tools is necessary. Ki-67 is commonly used as a marker of proliferation associated with tumor grade and lymph node metastasis. Methods: Samples were taken from penile cancer patients between 2013 to 2018, in the form of formalin-fixed paraffin-embedded (FFPE) blocks were analyzed. Patient demographic data, current and pre-cancer condition, cancer staging, outcomes, and other results of adjuncts and treatment modalities were obtained from medical records. Immunohistochemistry analysis was carried out on FFPE preparations. Under 20% of nuclei stained was considered as low-expression and more than 20% of nuclei stained was considered as Ki-67 over-expression. Data processing and analysis were carried out using SPSS software.  Results: In total, 48 FFPE samples were analyzed, with a mean patient age of 50.79 (±9.51 SD). For all patients, the type of pathology was squamous cell carcinoma. Node metastasis was positive in 34 patients (70.8%) and negative in 14 patients (29.2%). Statistical analysis was carried out using the Chi-Square test, resulting in a significant correlation between the expression of Ki-67 and lymph node metastasis in penile squamous cell carcinoma (p=0.045). Conclusion: Over-expression of Ki-67 were found in penile cancer patients with lymph node metastasis. Therefore, Ki-67 might be useful in predicting lymph node metastasis in penile cancer patients.