Expression of p53 and p63 proteins and their correlation with histological grades among gastric carcinoma specimens at Mbarara Regional Referral Hospital.

BACKGROUND: Gastric carcinoma remains one of the most common and deadly cancers worldwide, especially among older men. In sub-Saharan Africa and Uganda in particular, the diagnostic biomarkers of gastric carcinomas are not well documented; also, limited studies have been conducted in Uganda regarding the prognostic and diagnostic value of p53 and p63 immunohistochemical expression in gastric carcinomas. OBJECTIVE: We aimed to determine the immunohistochemical expression of p53 and p63 proteins and their correlation with different histological grades among archived gastric carcinoma specimens at Mbarara Regional Referral Hospital. METHODS: This was a laboratory-based cross-sectional study. We retrieved 166 archived formalin-fixed paraffin-embedded gastric carcinoma tissue specimens from the histopathology laboratory. They were stained with Harris haematoxylin and eosin stain and subsequently stained with p63 and p53 monoclonal antibody immunohistochemistry. RESULTS: Of the 166 gastric carcinoma specimens retrieved, almost a third of specimens were poorly differentiated (53/166; 32%) although the majority were moderately differentiated (68/166; 41%). P53 expression was 20/45 (44.4%), 27/68 (39.7) and 21/53 (39.6) in well-differentiated, moderately differentiated and poorly differentiated gastric carcinoma. Statistically significant positive correlation was observed between p63 and weak immunohistochemical expression (Spearman rho 0.155, p-value 0.047). CONCLUSION: P53 expression was more than p63 expression in different histological grades. There was no significant correlation of p53 with different histological grades but significant correlation was observed between p63 and moderately differentiated gastric carcinoma specimens. We recommend a prospective study using advanced molecular tests on fresh gastric carcinoma specimens to assess the prognostic usefulness of p53 and p63 biomarkers. WHAT THIS STUDY ADDS: This study provides the first Ugandan data on p53 and p63 expression in gastric carcinoma, highlighting p63's significant correlation with moderately differentiated tumours.