مجلة كلية الطب (Jul 2024)
The Correlation of P53 and MSI Immune Markers in Gastric Adenocarcinoma
Abstract
Background: The known risk factors for gastric adenocarcinoma are chromosomal instability, TP53 mutations, aneuploidy, translocations, proto-oncogenes, and tumor suppressor gene changes. Microsatellite instability (MSI) affects DNA replication accuracy and is detected by the heterodimeric protein complex hMSH2/hMSH6, which recruits hMLH1 and hPMS2 for re-synthesis. MSI can cause sporadic gastric cancer and Lynch syndrome. Objectives: To examine the relationship between P53 and MSI immune markers expression with the clinicopathological parameters of gastric adenocarcinoma by using immunohistochemistry. Materials and methods: The study examined 40 formalin-fixed, paraffin-embedded gastric adenocarcinoma tissue blocks. The samples were retrieved from archived materials in the histopathology department of the Gastroenterology and Hepatology Teaching Hospital, Teaching Laboratory Institute, and some private laboratories in Baghdad, Iraq. The samples were taken from patients between 2020 and 2023, while their retrieval spanned from October 2022 to October 2023 for the sake of examining primary cases, surgical tissues, and available clinicopathological data. The immunohistochemical (IHC) expression was assessed using a scoring system. Data were analyzed using SPSS, Chi-square, and Fisher's exact tests, with a 95% confidence level and a 0.05 P-value or less considered significant. Results: IHC staining for P53 was positive in 65% of the samples, while MSI findings were positive in 97.5% of the samples. The MLH1/PMS2 heterodimeric couple showed 32.5% positive results, while the MSH2/MSH6 heterodimeric couple showed 87.5% positive results. P53 stain was significantly correlated with lymph node involvement and grade, but not with the other parameters. No significant association was found between MSI markers and the studied parameters. There was no significant association between MSI heterodimeric couple (MLH1/PMS2) and the clinicopathological parameters, but there was a significant association between MSI heterodimeric couple (MSH2/MSH6) markers and metastasis only. Conclusion: P53 is a key biomarker for evaluating lymph node involvement and aggressiveness in grading, indicating prognosis, and identifying high-risk cancer patients for metastasis.
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