Assessment of microsatellite instability in colorectal carcinoma at an Indian center.
OBJECTIVE
The purpose of the present study was to evaluate the frequency of microsatellite instability (MSI) in colorectal cancers in an Indian cohort.


METHODS
Paraffin embedded tissue samples of colorectal cancers from 46 patients were assessed for mismatch repair protein expression (hMLH1 and hMSH2) by immunohistochemistry. Subsequently, MSI analysis was done after PCR amplification of five Bethesda markers.


RESULTS
Amongst 46 cases studied, only 5 patients (10.8%) showed MSI. Out of these, two (4.3%) had high microsatellite instability (MSI-H) and three (6.5%) showed low microsatellite instability (MSI-L). Out of 46 cases, 41 were microsatellite stable (MSS). In the 46 cases tested by immunohistochemistry, 7 (15.7%) showed the absence of hMLH1 and 1 case showed the absence of hMSH2.


CONCLUSIONS
Our study indicates a similar rate of incidence of MSI in colorectal cancers in the Indian cohort compared to the West (10-15%) despite lower incidence of colorectal cancers and predominance of rectosigmoid tumors in the Indian population.
Pandey
Vijay
V
Triesta Sciences, IPHCR Building, St. John's Medical College Campus, Opposite Koramangala BDA Complex, Bangalore, 560034, India. vijaypandey7@gmail.com
Prabhu
Jyothi S
JS
Payal
K
K
Rajan
Veena
V
Deepak
C
C
Barde
Shubhada
S
Jagannath
P
P
Borges
Anita
A
Sridhar
T S
TS
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011379:Prognosis
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein