Microsatellite Unstable Barrett's Esophagus-Associated Adenocarcinomas Are Rare, but Clinicopathologically Similar to the Colonic Counterpart
EG Demicco, AB Farris, AJ Iafrate, HA Gaissert, J Fukuoka, C Cohen, LR Zukerberg, GY Lauwers, M Mino-Kenudson. Massachusetts General Hospital, Boston; Emory University, Atlanta; Toyama Medical University, Toyama, Japan
Background: The frequency of microsatellite instability (MSI) has been reported inconsistently in Barrett's esophagus-associated adenocarcinoma (BEAd), and little is known about the clinicopathologic features of MSI high BEAds.
Design: Seventy-nine BEAds consecutively resected between 2000 and 2007 with available tissue blocks were evaluated by immunohistochemistry for MLH1, MSH2, MSH6 and PMS2 (MSI IHC). No cases underwent neoadjuvant therapy. Complete negative expression in any of the markers was considered to be positive. Several clinicopathologic features were examined in MSI IHC positive cases, and compared with those of MSI IHC negative cases.
Results: The study cases consisted of 69 males and 10 females with a mean age of 65 years. AJCC tumor and lymph node stages were pT1/2/3/4 = 35/10/33/1 and pN0/1/2/x = 45/31/2/1; the mean tumor size was 3.6 cm (4.7 cm for non-T1 tumors). Of those, 5 (6%) cases showed MLH1 and PMS2 loss. 3 of the 5 cases were further examined by PCR and were confirmed to have high-level MSI. Table 1 summarizes the clinicopathologic features of the 5 cases.
|Age (yrs)||Gender||Tumor size (cm)||pT||pN||Histology||Follow-up (mo)||Status|
|80||F||8.0||4||2||heterogeneous with medullary||14.8||dead of disease|
|79||M||5.5||3||1||heterogeneous with mucinous and signet ring cells||22.7||dead of disease|
|75||M||7.5||3||1||medullary||0.5||dead of complication|
|67||M||2.8||2||0||poorly differentiated with signet ring cells||10.7||dead of unknown cause|
|78||F||6.0||3||0||medullary||3.0||lost to follow-up|