Microsatellite instability is associated with the histological features tumor in nonfamilial colorectal cancer

Centro Ricerche Neoplasie Apparato Gastroenterico L. Novello, Ospedale San Giovanni Vecchio, Torino, Italy.
Cancer Research (Impact Factor: 9.33). 12/1996; 56(23):5470-4.
Source: PubMed


Replication errors (RERs) at microsatellite loci were examined in 46 specimens of nonfamilial colorectal cancer. Somatic microsatellite alterations in at least two genetic loci, D11S904, D13S175, D2S123, and D10S197, consistent with a RER(+) phenotype were found in four cases (8.7%). Six additional cases (13%) showed alterations at a single locus. Mucinous differentiation was observed in 3 of 4 (75%) adenocarcinomas with a RER(+) phenotype and only in 19% (8 of 42) of RER(-) adenocarcinomas (P < 0.05). A distinct cap of inflammatory cells at the advancing edge of the tumor and Crohn's-like reaction in peritumoral stroma were histologically identified in 50 and 25% of RER(+) and in 5 and 0% of RER(-) tumors, respectively (P < 0.05). Also, the plexiform pattern of growth of carcinoma turned out to be significantly associated with the RER(+) phenotype (P < 0.05). Mucinous differentiation and stromal inflammatory reactions are frequent features of hereditary nonpolyposis colorectal cancer in which germ-line mutations of mismatch repair genes cause genetic instability. Our results indicate that a link exists between such histological features and somatic genetic instability consistent with a RER(+) phenotype also in nonfamilial colorectal cancer.

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    • "Poorly differentiated colorectal carcinomas are quite rare, comprising only 3 – 5% of all colorectal carcinomas. It is well known that mucinous carcinoma is frequently observed in colorectal cancer with genetic instability, but the difference in genetic pathways between these histological types is mostly unknown because of the very small number of cases (Risio et al, 1996). "
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    • "So we were not able to determine whether these tumours showed partly chromosomic instability. MSI positive tumours have particular clinical and histopathological features (Lothe et al, 1993; Thibodeau et al, 1993, 1998; Kim et al, 1994; Risio et al, 1996; Rüschoff et al, 1997; Jass et al, 1998; Gafa et al, 2000). In our series, the different features associated with MSI status conformed with the characteristics described in the literature: the presence of a mucinous component, rather poor differentiation, a Crohn's like lymphoid stromal reaction and a trend towards a tumour of a larger size. "
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