Immunohistochemical expression of p53 in Type I and II epithelial ovarian cancer among Sudanese women: a cross-sectional study

Background:  Epithelial ovarian cancer (EOC) represents the leading cause of death from gynecologic malignancies worldwide. In Sudan, ovarian cancer represents the fourth most frequent tumors among females. TP53 somatic mutations is a defining feature of ovarian high-grade serous carcinoma. However, p53 sequencing is not feasible in most low- and middle-income countries, like Sudan, and its frequency varies greatly. The study aimed to determine the frequency of p53 overexpression and its relationship with tumor types I and II and tumor grade among Sudanese women with EOC. Methods: In this cross-sectional, hospital-based study a total of 114 paraffin-embedded tissue blocks previously diagnosed as epithelial ovarian cancer were collected from six governmental hospitals in Khartoum state, Sudan, in the period 2013-2016. Immunohistochemistry was performed on tissue microarray slides to measure the protein expression of p53 in the EOC. Results: Overexpression of p53 was detected in 35.1% (n=40/114) of  EOC samples, with a higher frequency in women with Type II 53.7% (n= 29/54)  than type I 18.5% (n= 10/54)  (P= 0.000). Also, a high frequency of p53 overexpression was evident in 49.2% (n= 30/61) of high-grade carcinoma compared with 16.7% (n= 1/6) of non-graded borderline tumors, and in 19.1% (n= 9/47) of low-grade tumors (P= 0.003). A high-grade serous carcinoma harbor p53 overexpression in 53.7% (n= 29/54) and none of low-grade serous carcinoma harbor p53 overexpression. Our result showed a significant association between p53 overexpression and tumor types and grades (P = 0.000 and 0.003, respectively) Conclusion: p53 over-expression was detected in one-third of Sudanese women with EOC.  It was more common in type II EOC and high-grade serous, but negative in low-grade serous tumors. Our result showed a significant association between p53 over-expression and tumor type and grade, and can help discriminate between high- and low-grade serous carcinomas.