Mismatch repair deficiency in sporadic synchronous colorectal cancer.
BACKGROUND
Hereditary non-polyposis colorectal cancer (HNPCC) patients frequently develop synchronous colorectal cancer (SCRC) which also occurs sporadically in other patients. Recent studies on microsatellite instability (MSI) in sporadic SCRC diverge completely in their findings (0%-100%). In the present study MSI and mismatch repair (MMR) proteins were evaluated according to standardised criteria (exclusion of a family history, MSI analysed according to NCI recommendations)


METHODS
Paraffin embedded sections of SCRC of 30 patients were evaluated for MSI and the loss of protein expression of hMLH1 and hMSH2.


RESULTS
3 out of 30 (10%) patients exhibited MSI-H which 5 out of 30 (17%) showed MSI-L. Loss of protein expression of either hMLH1 or hMSH2 was found in all cases of MSI-H and none of the MSI-L cancers.


CONCLUSIONS
MSI is found in sporadic cases of SCRC to about the same extent as it is mentioned in the literature on sporadic single colorectal cancers. Immunohistochemistry with mismatch repair proteins could be used as a pre-screening for MMR deficiency in sporadic SCRC.
Brueckl
W M
WM
Department of Internal Medicine I, University of Erlangen-Nuremberg, Krankenhausstr, 12, 91054 Erlangen, Germany. wolfgang.brueckl@med1.imed.uni-erlangen.de
Limmert
T
T
Brabletz
T
T
Guenther
K
K
Jung
A
A
Hermann
K
K
Wiest
G H
GH
Kirchner
T
T
Hohenberger
W
W
Hahn
E G
EG
Wein
A
A
D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D020137:Base Pair Mismatch; D002352:Carrier Proteins; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D004268:DNA-Binding Proteins; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein