Clinicopathologic Factors Associated with Mismatch Repair Status Among Filipino Patients with Young-Onset Colorectal Cancer
Received 17 October 2020
Accepted for publication 17 February 2021
Published 1 March 2021 Volume 2021:13 Pages 2105—2115
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Beicheng Sun
Dennis Lee Sacdalan,1– 3 Reynaldo L Garcia,2 Michele H Diwa,4 Danielle Benedict Sacdalan1,5
1Division of Medical Oncology, Department of Medicine, University of the Philippines, Manila, Philippines; 2National Institute of Molecular Biology and Biotechnology, University of the Philippines, Diliman, Quezon City, Philippines; 3Augusto P. Sarmiento Cancer Institute, The Medical City, Pasig City, Philippines; 4Department of Pathology, University of the Philippines, Manila, Philippines; 5Department of Pharmacology and Toxicology, University of the Philippines, Manila, Philippines
Correspondence: Dennis Lee Sacdalan
Division of Medical Oncology, Department of Medicine, University of the Philippines-Philippine General Hospital, Taft Avenue, Manila, 1000, Philippines
Tel/ Fax +63 285263775
Email [email protected]
Introduction: Young-onset colorectal cancer is recognized as a distinct disease that may be sporadic or hereditary in nature. Microsatellite instability testing is recommended as a routine procedure in evaluating colorectal cancer specimens, especially in young-onset disease, because of implications in management. Immunohistochemistry of mismatch repair proteins serves as an inexpensive alternative to microsatellite instability testing with the added advantage of monitoring protein expression levels that may suggest underlying genetic or epigenetic alterations. This descriptive study aimed to determine the frequencies of proficient and deficient mismatch repair status among Filipino young-onset colorectal cancer patients, and to investigate their clinicopathologic profile.
Methods: Tumor tissues were prospectively collected from patients from two tertiary hospitals in the Philippines. Patients of age ≤ 45 years with resected adenocarcinoma of the colon or rectum were recruited.
Results: Seventy-seven out of 124 patients had tumor samples sent for immunohistochemistry. Of these, 61 samples (79%) were found to have proficient status while 16 samples (21%) had deficient status. Mismatch repair protein deficiencies, when present, more commonly involved MSH2 and MSH6 (9%) rather than MLH1 and PMS2 (5%). The deficient group had a mean age of 37.1 years and a female preponderance (56.25%), presenting as locally advanced ascending or descending colon tumors with mucinous histology in half of the population. The mismatch repair proficient group presented as locally advanced rectal and sigmoid tumors but with fewer mucinous adenocarcinomas (26.2%) compared to the deficient group. In both the mismatch repair proficient and deficient patients with family history reports, most did not have any known relative with cancer (75.4% and 68.75%, respectively).
Conclusion: This is the first attempt to perform mismatch repair testing among young-onset colorectal cancer patients in the Philippines and to gather data on their clinicopathologic characteristics. However, the limited sample size precludes conclusive results for the associations of mismatch repair with clinicopathologic features.
Keywords: biomarkers, early-onset colorectal cancer, immunohistochemistry, microsatellite instability
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