Microsatellite Instability in Advanced Stage Endometrial Endometrioid Adenocarcinoma Is Associated with a Poor Prognosis.
Scott H Bradshaw, Russell Broaddus, Larissa Meyer, Bojana Djordjevic. Ottawa University, Ottawa, ON, Canada; M.D. Anderson Cancer Center, Houston, TX
Background: Microsatellite instability (MSI) arises due to loss of function of mismatch repair (MMR) proteins, commonly MLH1, MSH2 and MSH6, either through genetic loss or epigenetic silencing. There are only a few and conflicting reports on the prognostic value of MSI in endometrial cancer. The aim of this study was to investigate this parameter in endometrioid endometrial tumors with the emphasis on early vs. advanced stage disease.
Design: Immunohistochemistry for MMR proteins, MLH1, MSH2 and MSH6, was performed in 100 endometrioid carcinoma cases. The patients, aged 28-92, had no known history of HNPCC. Immunohistochemistry was scored as positive or negative. Tumors with loss of any one of the three MMR proteins were classified as having MSI, with the remainder classified as microsatellite stable (MSS). Patients were grouped as early (I and II) and advanced (III and IV) stage. Outcomes including depth of myometrial invasion (MI), lymphovascular invasion (LVI), lymph node (LN) status, relapse free survival and overall survival were examined.
Results: The results are summarized in tables 1 and 2.
|% Alive at last follow-up||96||100||1.00|
|% Relapse free||73||79||0.7597|
|% With LVI||29||47||0.2488|
|% With LN+||0||0||N/A|
|Median depth of MI (%)||26||33||0.7912|
|% Alive at last follow-up||95||58||0.0159|
|% Relapse free||67||25||0.0324|
|% With LVI||71||100||0.1247|
|% With LN+||61||78||0.6673|
|Median depth of MI (%)||42||82||0.0283|