Distinct relationship between polypoid growth type and sporadic colorectal carcinomas with microsatellite instability.
OBJECTIVE
This study was carried out to clarify whether colorectal carcinomas with MSI (microsatellite instability) is correlated with growth types of invasive carcinomas.


METHODS
Samples of tumor tissue and adjacent normal mucosa were obtained from 45 patients with sporadic advanced colorectal cancer. The MSI was assessed by the mobility shift assay of microsatellite and VNTR (variable numbers of tandem repeat) alleles using 12 markers. Tumors with four or more positive loci were determined to be MSI positive. The polyadenine tract (A)10 of the third exon in TGF beta RII was also assessed by mobility shift assay of DNA fragments amplified with primers. Histological examination was performed to divide all tumors into polypoid growth carcinoma and nonpolypoid growth carcinoma, according to Shimoda et al.'s classification.


RESULTS
Ten of 11 cases with MSI had a 1-base pair deletion in a polyadenine tract in the TGF beta RII gene. Fifteen cases showed polypoid growth and 30 cases indicated nonpolypoid growth. There were 9 polypoid growth cases and 2 nonpolypoid growth cases with MSI, while there were 6 polypoid growth cases and 28 nonpolypoid growth cases without MSI. Colorectal cancer cases with MSI had a significantly higher incidence of cases with polypoid growth (9/11) compared to those without MSI (6/34) (P = 0.0004).


CONCLUSIONS
Sporadic colorectal carcinomas with MSI tend to show a polypoid growth type. We think that there are two types including "adenoma-carcinoma sequence" type and "RER" type in colorectal carcinomas that show adenoma-carcinoma progression.
Komura
K
K
Third Department of Surgery, Nihon University School of Medicine, 2-11-1, Hikarigaoka, Nerima-ku, Tokyo 179-0072, Japan.
Masuda
H
H
Esumi
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D003111:Colonic Polyps / Q000235:genetics* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D018598:Minisatellite Repeats; D009361:Neoplasm Invasiveness; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics
D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II