Lynch Syndrome-Associated Endometrial Cancer With Combined EPCAM-MSH2 Deletion: A Case Report.

Rong Huang,Qinglian Wen,Dan Li,Xiangyu Deng,Zhenhua Zhang

doi:10.3389/fonc.2022.856452

Abstract

BackgroundLynch syndrome (LS), an autosomal dominant disorder, is characterized by germline pathogenic variants in DNA mismatch repair (MMR) genes like MSH2. EPCAM deletions cause a minority (3%) of LS cases. However, there are only a few reports of LS-associated endometrial cancer (LS-EC) induced by the inactivation of the MSH2 gene due to EPCAM deletions.Case PresentationWe present the case of a 45-years old woman diagnosed with endometrial cancer (EC). Definitive surgery revealed meso-differentiated endometrioid adenocarcinoma, stage IA without lymph-vascular space invasion. Four months later, she received radiation therapy (125I radioactive seeds implantation), and platinum-containing regimen combined chemotherapy because of vaginal stump metastasis of EC. After five years, we performed immunohistochemistry (IHC) on pelvic mass because of presacral metastatic lymph node. IHC showed the absence of MSH2 and MSH6 protein expression in the pelvic mass tissue. Peripheral blood was used for genetic testing based on her cancer diagnosis and family history of cancer in close relatives. Genetic testing revealed deletions of exon 8 and 9 in EPCAM and deletions of exon 1 and 8 in MSH2; thus, we diagnosed the presence of LS. The patient underwent interstitial brachytherapy (BT) of the presacral metastatic lymph node.ConclusionThis case highlights that patients with LS-EC who are carriers of combined EPCAM-MSH2 deletion might experience better oncologic outcomes even with early recurrence.

Highlights

Lynch syndrome (LS) is caused by germline pathogenic variants (PVs) in one of the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2) or by deletions in the epithelial cell adhesion molecule gene (EPCAM), which increases susceptibility to colorectal and endometrial cancers and other tumors [1–3]
Up to 3% of LS cases are due to variants involving the 3’ end of the EPCAM gene, which result in hypermethylation of the MSH2 promoter or partial deletion of MSH2 [6, 7]
The difference in tumor occurrence or spectrum resulting from MSH2 mutation carriers versus EPCAM deletion carriers may be related to the mosaic pattern of MSH2 inactivation displayed by EPCAM deletion carriers [8, 9]

Summary

Background

Lynch syndrome (LS), an autosomal dominant disorder, is characterized by germline pathogenic variants in DNA mismatch repair (MMR) genes like MSH2. There are only a few reports of LSassociated endometrial cancer (LS-EC) induced by the inactivation of the MSH2 gene due to EPCAM deletions. Case Presentation: We present the case of a 45-years old woman diagnosed with endometrial cancer (EC). Definitive surgery revealed meso-differentiated endometrioid adenocarcinoma, stage IA without lymph-vascular space invasion. Four months later, she received radiation therapy (125I radioactive seeds implantation), and platinum-containing regimen combined chemotherapy because of vaginal stump metastasis of EC. We performed immunohistochemistry (IHC) on pelvic mass because of presacral metastatic lymph node. Genetic testing revealed deletions of exon 8 and 9 in EPCAM and deletions of exon 1 and 8 in MSH2; we diagnosed the presence of LS. The patient underwent interstitial brachytherapy (BT) of the presacral metastatic lymph node

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