Browsing by Subject "Colorectal tumours"

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    Bcl-2 expression in colorectal tumours. Correlation with p53, mdm-2, Rb proteins and proliferation indices
    (Murcia : F. Hernández, 2000) Goussia, A.C.; Loachim, E.; Agnantis, N.J.; Mahera, M.; Tsianos, E.V.
    Immunostaining for bcl-2 protein was performed in 27 colorectal adenomas and 108 colorectal adenocarcinomas. The aim of the study was to determine bcl-2 expression in correlation with p53, mdm-2 and Rb expression, with proliferation indices (Ki-67-LI, PCNALI) as well as with conventional clinicopathological variables. A higher proportion of adenomas (30.8%) than carcinomas (16.7%) expressed bcl-2 and conversely, a lower proportion of adenomas (7.4%) than carcinomas expressed p53 (57.1 %), the difference being statistically significant (p<0.0001). No correlation of bcl-2 expression with p53 expression (parallel or inverse) as well as with the other parameters studied was observed in any tumour. The bcl-2+/p53- subgroup of cancers showed a trend for correlation with negative lymph node status. Our data suggest, that bcl-2 expression may be involved in the early phase of colorectal carcinogenesis regardless of p53 status, while p53 function may be involved in a late stage of the adenoma-carcinoma sequence. P53 is apparently not involved in the regulation of apoptosis in the colorectal neoplasias or perhaps bcl-2 expression, as an early event in colorectal tumours, may occur before changes of p53 take place. Tumours with bcl-2+/p53- immunophenotype are frequently associated with negative lymph node status and seem to have a less aggressive behavior.
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    Iron-binding proteins in human colorectal adenomas and carcinomas: an immunocytochemical investigation
    (Murcia : F. Hernández, 1992) Tuccari, G.; Rizzo, A.; Crisafulli, C.; Barresi, G.
    By immunocytochemistry, the presence of major iron-binding proteins (lactoferrin, transferrin and ferritin) was investigated in tubular adenomas (12 cases), villous adenomas (7 cases), carcinomas of the large bowel and rectum (39 cases) and lymph nodes involved in carcinomas (8 cases); 5 samples of colonic inflarnrnatory pseudopolyps were aiso studied. Dysplastic areas of tubular and villous adenomas as well as adenocarcinomas and colloid carcinomas showed a variable cytoplasmic immunoreactivity for al1 antisera, although no staining was noted in some cases; tubular adenomas without dysplasia and colonic inflarnmatory pseudopolyps were always unstained. Metastatic elements present in lymph nodes maintained the irnmunohistochemicai staining for iron-binding proteins. An autoctone production of lactoferrin, transferrin and ferritin by tumour cells may be hypothesized in relation to the increased requirement of iron for the tumover of rapidly dividing cells.