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PubMed2002

Evaluation of telomerase in the development and progression of colon cancer.

Telomerase activity, a cardinal requirement for immortalization, is a crucial step in the development of cancer and has been studied in many kinds of malignant tumours for clinical diagnostic and/or prognostic utilities. Using a PCR-based TRAP assay, we investigated telomerase activity in 8 adenomatous polyps, 9 dysplastic polyps, and in 36 paired cancer-normal mucosa specimens, one liver and one spleen metastasis from patients resected for sporadic colorectal cancer. Telomerase was absent or very low in normal mucosa and in adenomatous polyps. Dysplastic polyps and adenocarcinoma samples showed telomerase activity, with higher levels in cancer tissues compared to dysplastic lesions. A high telomerase activity was shown to be associated with late-staged cancers and metastasis, providing arguments supporting the role of telomerase not only in the development but also in the progression of colorectal carcinoma. Moreover, telomerase evaluation may help to confirm the malignant transformation in polypoid colorectal lesions with different levels of dysplastic alterations.

Adenocarcinoma↗
PubMed1992

[Flow cytometric analysis of colorectal cancer and polyps].

Thirty-four cases of colorectal cancer, 24 cases of polyps of various types and 30 cases of control colorectal mucosa were analysed by flow cytometry for DNA content in order to study their relation to histopathology and prognosis. The result showed that the DNA content of 6 out of 24 polyps (25%) were aneuploid, and all of these 6 cases with aneuploid DNA content were adenomas accompanied with mild to severe dysplasia, and six cases of juvenile polyps were diploid. There was a correlation between DNA aneuploid and severe dysplasia (P less than 0.05), but not with the histopathologic type. Twenty-three out of 34 cancers were aneuploid (68%), and correlation was noticed between the DNA Index (DI) and Dukes' classification (F = 17.37), but not with the differentiation of tumors. Patients with DNA aneuploid tumours had a worse prognosis than those with only DNA diploid tumours. Therefore, DNA ploidy of colorectal cancers detected by flow cytometry is of prognostic value for colorectal cancer.

Adenoma↗
PubMed1990

[Clinico-pathological studies on Is, Ip polyps and flat elevations in the large intestine].

We histologically compared 3 types of adenoma and cancer of the large intestine using 620 adenoma specimens (509 Is type lesions, 83 Ip type lesions, and 28 flat type lesions) and 113 specimens of early stage cancer (51 Is type lesions, 39 Ip type lesions, and 23 flat type lesions) obtained during the past 5-year period at our department. More than 90% of the Is and Ip type polyps were adenoma or carcinoma in adenoma while 25.5% of the flat elevations were m or sm carcinoma. Flat elevations even less than 10 mm in diameter were frequently carcinomas (26.3%) compared with the other types (both Is and Ip types, 6.7%), and all of those 10 mm or more in size were carcinomas. The distribution of the flat type early cancers in the large intestine was similar to that of advanced cancer with high percentages of carcinoma at each site compared with the other types. These results suggest that the carcinogenesis and progression of flat type early stage cancer differ from those of the other types.

Adenoma↗
PubMed1989

Expression of the c-erbB-2 gene product (p185) at different stages of neoplastic progression in the colon.

The c-erbB-2 gene has been found amplified in a number of human adenocarcinomas leading to elevated levels of expression of the p185 protein product. Increased expression of this putative growth factor receptor has been reported to occur by molecular mechanism other than gene amplification and for this reason we have studied the expression of the p185 protein in normal colon and in lesions representing different stages of neoplastic progression. We report amplification of the c-erbB-2 gene in 3 of 44 colon carcinomas and 1 of 5 preneoplastic polyps studied. Confirmation of expression of the p185 protein product was established in Western blot analysis and by immunocytochemical staining of tissue sections. An extended study, involving adenomatous polyps and carcinomatous material in immunostaining, revealed detectable presence of the p185 protein in 20% of carcinomas, consistent with immunoprecipitation data derived using established cell lines. In contrast, a high percentage of polyps showed strong staining with both p185 antibodies used, indicating elevated levels of expression of the c-erbB-2 protein associated with preneoplastic lesions. Staining of normal human colon revealed a restricted localization of this putative receptor to cells on the luminal colonic surface, with no expression in cells of the crypt. Histologically normal mucosa, adjacent to the tumor, showed a more extensive distribution involving the crypt suggestive of a disturbance in the normal expression of c-erbB-2. These results indicate that elevated expression of the c-erbB-2 protein is associated with early stages of colonic neoplasia but do not establish it as a primary factor in these events. The occurrence of multiple copies of the c-erbB-2 in a percentage of colon lesions, however, suggests a possible role for this gene in some colon malignancies.

Antibody Specificity↗
PubMed1988

[Risk diseases for colorectal cancer].

Among the risk conditions with an increased prevalence or incidence of colorectal carcinomas hereditary and acquired disorders have to be differentiated. While in hereditary forms new in vitro tests may play a role in the identification of patients at risk we have to rely on screening and follow-up programmes in the other group of patients. The intervals of these surveillance programmes should be acceptable to the patient since many risk groups seem to be questionable on a cost-benefit evaluation.

Colonic Neoplasms↗
PubMed1988

[Colorectal cancer. Precancerous conditions].

Colorectal precancerous stages are primarily benign lesions of the colon mucosa with a potential to malignant degeneration. They are macroscopically seen as polypoid lesions, but not only "adenomas" are to be seen as precancerous. Polypoid lesions which are not of neoplastic origin are not capable of malignant degeneration. Precancerous dysplasias are also found in the flat atrophic mucosa of chronically inflamed colon mucosa , which complicates the macroscopical judgement in the endoscopy. Problems also arise for the pathologist in the separation between inflammatory regenerative epithelatypia and high-grade dysplasia.

Colonic Neoplasms↗
PubMed1988

[Multiple colorectal cancers: properties and long-term prognosis].

In our own patient population with primary colorectal cancer (n = 1352, 1971-1984) we analyzed the frequency, characteristics and prognosis of multiple carcinomas. The overall incidence was 7.3% (4.5% synchronous and 2.8% metachronous carcinomas). Compared to single cancer synchronous tumors had a worse and metachronous tumors had a better 5 year-prognosis (58%, 43% and 86% respectively). This suggests that synchronous and metachronous colorectal carcinomas may be two biologically separate entities. Conclusions from our observations are discussed in regard to diagnosis, therapy and follow-up.

Colonic Neoplasms↗
PubMed1986

Radiologic diagnosis of invasive carcinoma on adenomatous polyps of the colon.

The radiographic appearance at double contrast enema of 33 cases of invasive cancer on adenomatous polyps (AP) of the colon is reviewed. The radiologic diagnosis of malignancy was prospectively made in 54.5% of the cases. In 45.5% of the cases, malignancy was not suspected at the time of examination. The endoscopic appearance of these lesions was identical to that seen on the barium study. There are no radiologic criteria able to entirely rule out the possibility of a carcinomatous transformation of an AP. However, the radiologic features of malignancy (indentation of the intestinal wall and/or irregular outline of the surface of the polyp) have to be considered quite reliable.

Adenocarcinoma↗