DNA mismatch repair deficiency in ampullary carcinoma: a morphologic and immunohistochemical study of 54 cases.
The significance of DNA mismatch repair (MMR) deficiency or microsatellite instability (MSI) in ampullary carcinomas remains to be defined. This study evaluated the MMR status in 54 consecutive ampullary adenocarcinomas by immunohistochemical and morphologic studies. All tumors were moderately (n = 49) or poorly (n = 5) differentiated, with 7 mucinous and 1 signet-ring cell type. Tumor-infiltrating lymphocytes (TILs) were noted in 36 tumors. Loss of MMR protein by immunohistochemical analysis was identified in 3 (6%), 2 lost MSH6, and 1 lost MLH1/PMS2. One MSH6- case had 3 metachronous colorectal cancers. Five TILs per 10 high-power fields predicted immunohistochemical abnormality in 2 of 3 tumors with a specificity of 80% (41/51); however, none of the 5 tumors that had the highest TIL counts (20-62/10 high-power fields) showed abnormal immunohistochemical results. Thus, MMR deficiency occurs in ampullary carcinoma but appears less frequent than in colorectal carcinoma (CRC). Typical MSI-high histologic features of CRC, such as increased TIL counts, seem to have similar yet subtly different implications in ampullary carcinoma.
Agaram
Narasimhan P
NP
Dept of Pathology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA.
Shia
Jinru
J
Tang
Laura H
LH
Klimstra
David S
DS
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000236:Adenoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014670:Ampulla of Vater / Q000378:metabolism / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D003138:Common Bile Duct Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D053843:DNA Mismatch Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein