Early detection of liver metastasis in patients with colorectal carcinoma by increased levels of circulating IgA- and IgM-associated secretory component.

One hundred patients operated for colorectal carcinoma were followed clinically and with serial blood samples from 5 to 8 years. Levels of secretory component (SC) associated with IgA and IgM in serum were measured and related to Dukes' stage, histological differentiation, tumour expression of SC, and circulating carcinoembryonic antigen (CEA). On the whole, elevated levels of SC in serum were found in 15 of the 20 patients who already had (n = 15), or later developed (n = 5), liver metastasis. Four of the latter 5 patients showed raised SC levels with a 5.5 months median lead time from the first positive serum sample to clinically manifest liver disease. These data are interesting in view of the promising results reported for liver resection in patients with colorectal carcinoma

Is heterogeneous expression of HLA-dr antigens and CEA along with DNA-profile variations evidence of phenotypic instability and clonal proliferation in human large bowel carcinomas?

Epithelial expression of HLA-DR determinants and CEA was studied by immunofluorescence in tissue sections from 33 large bowel carcinomas of different histological grade and clinico-pathological stage; flow cytometric DNA measurements were performed in 31 of the tumours. Well-differentiated carcinomas showed a strikingly patchy staining, particularly for HLA-DR and all except one had a near-diploid DNA content. The latter feature might reflect cancer development at an early stage where no distinctly aneuploid DNA clone had as yet become a predominant subline. With decreasing degree of differentiation, the epithelial antigen expression became more homogeneous for individual tumours and the proportion of distinctly aneuploid DNA profiles increased. In the poorly differentiated group of carcinomas, epithelial staining was quite uniform, both for HLA-DR determinants and for CEA, and those tumours studied for DNA content were of the aneuploid variety. These observations are in agreement with the clonal proliferation theory of tumour development proposed by Nowell in 1976

Heterogeneous epithelial expression of class II (HLA-DR) determinants and secretory component related to dysplasia in ulcerative colitis.

The intensity and degree of heterogeneous epithelial marker expression were evaluated immunohistochemically in 29 mucosal biopsy specimens from 7 ulcerative colitis (UC) patients with dysplasia. Biopsy specimens from UC patients with mild (n = 7) or severe (n = 6) inflammation and from histologically normal samples (n = 7) served as controls. HLA-DR showed heterogeneous epithelial expression in all lesions with high grade dysplasia and in 6 of 8 with low grade dysplasia. SC was heterogeneous stained in 17 of 21 lesions with high grade dysplasia and in all but two lesions with low grade dysplasia. In histologically normal mucosa, SC was homogeneously expressed and epithelial DR was virtually absent. In mildly inflamed UC lesions, SC exhibited patchy distribution in only one sample and DR in two, whereas both SC and DR showed a slight degree of heterogeneous expression in all lesions with severe inflammation. Moreover, the overall intensity of SC staining tended to decrease with increasing degree of inflammation, whereas the opposite was seen for DR. Decreased SC and increased DR expression thus seemed to be related to intensified inflammatory activity, whereas heterogeneous expression of these markers was significantly more related to dysplasia

K-ras mutation in colorectal cancer: relations to patient age, sex and tumour location.

DNA from 251 primary tumours obtained from 123 male and 125 female Norwegian patients with colorectal carcinoma was analysed for the presence of K-ras point mutations at codons 12 and 13. Mutations were found in 99 (39%) of the samples. The frequency of K-ras mutations was significantly related to age and sex of the patients, and to the location of the tumours (overall: P = 0.008). K-ras mutations were much less frequent in colonic tumours from male than female patients at younger ages (< 40 years, odds ratio < 0.014). The low frequency might indicate that a different, ras-independent, pathway to neoplasia is dominating in the colon of younger males. In contrast, older men had more mutations than older women (e.g. 90 years, odds ratio = 5.8). An inverse but less pronounced relationship was seen for rectal tumours. The type of mutation was found to be associated to sex of patient and location of tumour. G-->C transversions accounted for 35% of the mutations in rectal tumours from females, in contrast to only 2.5% in the rest of the material (P = 0.0005). This may indicate that there are specific carcinogens acting in this location

Large-bowel carcinomas with different ploidy, related to secretory component, IgA, and CEA in epithelium and plasma.

Immunofluorescence staining for carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA was evaluated semiquantitatively in 85 large-bowel carcinomas in relation to degree of tumour differentiation, Dukes' stage, and plasma CEA level. The tumours were divided into a near-diploid (ND, 28) and an aneuploid group (AN, 57) by means of flow-cytometric DNA measurements. Expression of SC and IgA in neoplastic epithelium was positively related to differentiation in both groups. The AN tumours scored significantly higher for CEA than the ND ones, but the staining was apparently unrelated to differentiation or Dukes' stage. CEA expression in the transitional mucosa adjacent to ND tumours was negatively correlated with tumour differentiation, whereas epithelial IgA and SC in this zone showed a substantially higher positive correlation with tumour differentiation, and a somewhat stronger negative correlation with Dukes' stage in the ND than in the AN group. Plasma CEA levels were significantly related to Dukes' stage, only in patients with AN tumours, and only in this group were positively correlated with estimates of total tumour CEA for Dukes' stages A and B. For Dukes' stages C and D (disseminated tumours), moreover, the plasma CEA levels were found to be significantly higher in the AN group. These findings indicate that the DNA profile of large-bowel carcinomas is related both to the way neoplastic cells influence the activity of the transitional mucosa and their capacity for expression and release of epithelial products. AN tumours thus seem to be more active as "secretors" of CEA than ND ones

Strong HLA-DR expression in large bowel carcinomas is associated with good prognosis.

One hundred large bowel carcinomas operated on between 1978 and 1982 were studied immunohistochemically with regard to expression of HLA-DR antigens. Three sections from each tumour were investigated by a semiquantitative scoring system, and a mean score for each patient established. Based on this scoring system, the tumours were divided into three groups: 0; 0.1-1.0; and > 1.0. All patients were followed until death (n = 68) or until June 1, 1992, and all cancer-specific deaths (n = 56) have been recorded. Analysis of survival in the whole patient group showed significant difference between the three levels of tumour HLA-DR expression (P = 0.006); patients who had tumours with strong HLA-DR expression showing the best survival. In a stratified analysis after Dukes' stages there was still a significant difference (P > 0.001) between the three levels of HLA-DR staining intensity. After a multiple regression analysis (Cox) with correction for different variables, the HLA-DR expression maintained its significance as a risk factor. To our knowledge this is the first time a relationship between intensity of tumour DR expression and survival has been shown in large bowel carcinoma

Flow cytometric DNA ploidy pattern in dysplastic mucosa, and in primary and metastatic carcinomas in patients with longstanding ulcerative colitis.

Eighty-nine fresh tissue samples from flat colonic mucosa, polypoid lesions, macroscopically evident carcinomas, and metastatic carcinomas from ten patients with longstanding ulcerative colitis (greater than or equal to 8 years duration) were analysed by DNA flow cytometry and light microscopy. Of a total of ten carcinomas found in six patients, six showed DNA aneuploidy. Three patients developed metastatic carcinomas, all with aneuploid cell populations with similar DNA indices as in the primary carcinoma. Furthermore, aneuploid cell populations with similar DNA indices often occurred, both in separate mucosa samples, as well as in mucosa and carcinoma samples, from the same patient. DNA aneuploidy was found in flat mucosa in five of the six patients with carcinoma, and in one of the four patients without carcinoma (P greater than 0.1). High grade dysplasia was found in only four of the six cases with carcinoma, indicating that high grade dysplasia is insufficient as marker for malignant development. DNA aneuploidy was found in 24% of the dysplastic mucosa samples, and in 18% of the non-dysplastic mucosa samples (n.s., both with regard to high and low grade dysplasia). Since abnormal DNA ploidy pattern was not confined to dysplastic epithelium only, DNA aneuploidy in flat mucosa may constitute an additional marker in the identification of patients at increased cancer risk who could benefit from a closer surveillance

Secretory component mRNA and protein expression in colorectal adenomas and carcinomas.

Secretary component (SC) is expressed basolaterally as a transmembrane protein (pIg receptor) on secretory epithelial cells. As pIg receptor it plays a central role in humoral immunity by mediating the external translocation of dimeric IgA and pentameric IgM. A few case reports have suggested that reduced or absent SC protein expression is associated with diarrhoeal disease, but there is no convincing evidence that a primary pIg receptor deficiency can occur. In this study the relative presence of SC mRNA was determined by Northern blot analysis and related to immunohistochemically determined SC protein expression in 33 colorectal adenomas (31 patients) with increased risk of developing sporadic colorectal cancer, as well as in 19 colorectal carcinomas from 19 patients with such sporadic tumours. In the adenomas, SC mRNA levels were positively related to SC protein expression; both mRNA and SC protein were negatively related to histological grade. Similarly, SC mRNA levels tended to be related to the SC protein expression in the carcinomas. SC mRNA was detected in all adenomas, and only two of ten carcinomas (10.5%) deemed to be SC deficient by immunohistochemistry also lacked SC mRNA expression, suggesting diallelic alterations in the SC-encoding gene (locus PIGR). This possibility agreed with Southern blot analysis performed on a separate sample of 32 other colonic carcinomas in which the diallelic loss of D1S58 (which exhibits a close linkage centromerically to PIGR) was calculated to be 6.4%. Together these findings suggested that reduced SC protein expression in colorectal adenomas might be a transcriptional defect reflecting the degree of cellular dysplasia, whereas absent SC protein expression in colorectal carcinomas might also involve post-transcriptional defects and occasional diallelic gene deletions representing late events in carcinogenesis

Genetic alterations within the retinoblastoma locus in colorectal carcinomas. Relation to DNA ploidy pattern studied by flow cytometric analysis.

Alterations within the retinoblastoma (Rb) gene, as detected by the VNTR probe p68RS2.0, and flow cytometric DNA pattern have been analysed in 255 colorectal carcinomas. A total of 35.3% of the tumours had alterations within the Rb gene. Amplification of one allele was demonstrated in 29.5% of the tumours, and loss of heterozygosity was found in 11.5%. No association was found between amplification within the Rb gene and clinicopathological characteristics of the patients. The high frequency of alterations demonstrated within the Rb gene, suggests that this gene is involved in colorectal carcinogenesis with amplification as by far the most abundant genetic alteration. This may imply that the Rb gene has an oncogene-like function in colorectal carcinomas, rather than acting as a tumour suppressor gene. Sixty-three per cent of the carcinomas were DNA aneuploid, and a significant association was demonstrated between amplification within the Rb gene and DNA aneuploidy (P less than 0.01). Two other chromosome loci were analysed, on chromosome 1p (probe pYNZ2) and on chromosome 2p (probe pYNH24), respectively. On chromosome 1p, heterozygous loss was found in 22.2% of the tumours, indicating an involvement of this chromosome in a subset of colorectal carcinomas

The TP53 tumour suppressor gene in colorectal carcinomas. I. Genetic alterations on chromosome 17.

In 231 colorectal carcinomas, allele variation at four restriction fragments length polymorphisms (RFLP) loci on chromosome 17 have been studied by Southern analysis. Heterozygous loss of the TP53 gene was found in 68% (129/189) of the carcinomas informative on both chromosome arms. In 41% (77/189) of the carcinomas the loss was found only on 17p. Two probes were used to detect alterations on 17p, pBHP53 and pYNZ22. When loss was demonstrated with pYNZ22, pBHP53 also always showed loss (n = 45), whereas when loss was demonstrated with pBHP53, only 45 of 54 (83%) showed loss with pYNZ22. Loss on 17q was found in 34% (64/189) of the carcinomas, and 6% (12/189) had loss on this chromosome arm, only. Loss on 17q was significantly associated with loss on 17p (P < 0.01). These data confirm that the TP53 gene is the target of loss on chromosome arm 17p in colorectal carcinomas, and demonstrate that loss of the TP53 gene is most frequently part of limited, subchromosomal loss. Furthermore, the results do not suggest any additional tumour suppressor gene(s) on chromosome 17 involved in colorectal carcinogenesis