The presence of oncofoetal antigens in large bowel carcinoma

Intestinal mucin antigens in ulcerative colitis and their relationship with malignancy

The expression of two intestinal mucin-associated antigens large intestine mucin antigen (LIMA) and small intestine mucin antigen (SIMA) were investigated by indirect immunoperoxidase staining of rectal mucosa from patients suffering from ulcerative colitis with (n = 6) and without (n = 31) associated carcinoma and in noncolitic controls (n = 40). The aim was to assess the relationship between antigen patterns and malignant change. SIMA, which is localised predominantly in the small intestine, is virtually undetectable in the normal adult colonic mucosa. However, this antigen is present in the foetal colon and colonic carcinoma. LIMA is expressed in normal colonic mucosa, but absent from the small intestine. LIMA staining patterns were not significantly different among the three groups. In contrast, expression of SIMA was significantly higher in the patients who had developed carcinoma (6/6) than in the noncancer group (7/71) (P less than 0.001). The presence of SIMA was also significantly related to areas of dysplasia compared to normal (P = .03) or inflammation (P less than .05), but it did not differ from mucosa showing "indefinite" atypia. The finding of 31% SIMA-positive biopsies associated with severe inflammation in colitis with active disease, but no evidence of malignancy, is difficult to explain at the present stage. A followup study would be necessary to determine its significance. Perhaps the most important finding is the increased frequency of SIMA-positive foci in histologically normal mucosa in carcinoma patients compared with the noncancer group (P less than .001), suggesting a field change. These observations may be prove useful for the identification of patients who may be at risk of developing carcinoma.

DNA content in carcinoma of the rectum and rectosigmoid

Using single cell cytometry the pattern of DNA content in preoperative samples from 131 carcinomas of the rectum and rectosigmoid has been studied. For comparison, 21 carcinomas of the colon, 44 colorectal polyps and mucosa adjacent to the tumours were also included. The biopsies were classified into near diploid (ND), near diploid with aneuploid cells (ND-anc) and aneuploid (AN). A more specific subclassification of aneuploid samples was not consistent because of a commonly occurring multiclonality, where different clones dominated different parts of the tumours. Fifteen of all 130 representatively sampled rectal carcinomas were ND; however, all the ND scores were based on a single sample. Among 31 multiply-sampled carcinomas none registered as ND in all samples. There were no principal differences in patterns of DNA profiles between rectal and colon carcinomas. Five samples from the pericancerous mucosa and samples from 4 adenomas showed non-ND patterns, which may be a premalignant sign. The main conclusions of these results are that rectal carcinomas, even if they contain a substantial ND cell population, to a very great extent contains cells with an abnormal DNA content. The carcinomas can be classified according to their pre-operatively estimated DNA content. The clinical relevance of this will be judged when the patients have been followed for longer time periods.

Further studies of intestinal heterotopia in urethral caruncle

Colonic mucosa-like intestinal heterotopia in a urethral caruncle is reported in a 2 yr 7 mth old girl and three women; 55, 71 and 78 yrs old. The occurrence of the anomaly in a child supports the first two author's earlier suggestion that the condition is congenital in nature. In princip this could also be the case in post-menopausal women, although the possibility of metaplasia must also be considered. Perhaps the condition could be a precursor of some adenocarcinomas of the distal urethra.

Sialomucins and carcinoembryonic antigen in the evolution of colorectal cancer

We have explored the merit of a simultaneous study of sialomucin content and carcinoembryonic antigen (CEA) expression in the identification of early malignancy in adenomas. One hundred and thirteen colorectal adenomas were investigated by histochemical and immunocytochemical techniques. We compared adenomas from 'high risk' patients having synchronous carcinoma and 'low risk' groups with incidental polyps only. Twenty-three metaplastic and eight inflammatory polyps were also included. Our data suggest that size and dysplasia are not always closely related and that synchronous adenomas seem to carry a higher malignant potential than incidental polyps irrespective of size. The degree of O-acylation of sialic acids appears to be a sensitive indicator of early malignant change: loss of O-acylation was seen in all II adenomas with highly atypical foci ('focal carcinoma') but noted in only four of the remaining polyps with lower grade dysplasia (P less than 0.005). By contrast the intensity of staining for CEA was a gradual phenomenon and showed no statistically significant increase with the onset of malignancy. Inflammatory polyps showed staining characteristics similar to normal mucosa. Metaplastic polyps, however, revealed increased expression of CEA and reduced O-acylation with increased size which may reflect a disorder of growth and differentiation. Finally, by comparing these profiles of staining with those of normal mucosa, 'transitional' mucosa adjacent to carcinoma and carcinoma, we further illustrate a progression of changes occurring in colonic mucosa in carcinogenesis.

Inappropriate mucin production in endodermal carcinoma--one point of view

The mucosal lining cells in the gastrointestinal tract respond to a threatening situation by secreting mucins manufactured during foetal life and this secretion is considered to be an early manifestation of cytogenetic instability and which may be the first step in the process of malignant transformation. Using immunohistological techniques and specific antisera against SIMA (small intestinal mucin antigen), LIMA (large intestinal mucin antigen) and CEA (carcinoembryonic antigen) the presence of these mucin antigens was studied in resected specimens from colonic, gastric and gall bladder carcinomas as well as in mucinous tumours of the ovary. Inappropriate or oncofoetal mucins were present in the majority of endodermal carcinomas, in associated metaplastic epithelium and premalignant lesions such as polyps. These antigens were also demonstrated in normal histological epithelium at some distance from the tumour. These findings lead to a better understanding of the biological behaviour of preneoplastic lesions of endodermal tissues and will aid in developing sensitive diagnostic tests for the presence of these substances.