COL11A1 in FAP polyps and in sporadic colorectal tumors

BACKGROUND: We previously reported that the α-1 chain of type 11 collagen (COL11A1), not normally expressed in the colon, was up-regulated in stromal fibroblasts in most sporadic colorectal carcinomas. Patients with germline mutations in the APC gene show, besides colonic polyposis, symptoms of stromal fibroblast involvement, which could be related to COL11A1 expression. Most colorectal carcinomas are suggested to be a result of an activated Wnt- pathway, most often involving an inactivation of the APC gene or activation of β-catenin. METHODS: We used normal and polyp tissue samples from one FAP patient and a set of 37 sporadic colorectal carcinomas to find out if the up-regulation of COL11A1 was associated with an active APC/β-catenin pathway. RESULTS: In this study we found a statistically significant difference in COL11A1 expression between normal tissue and adenomas from one FAP patient, and all adenomas gave evidence for an active APC/β-catenin pathway. An active Wnt pathway has been suggested to involve stromal expression of WISP-1. We found a strong correlation between WISP-1 and COL11A1 expression in sporadic carcinomas. CONCLUSIONS: Our results suggest that expression of COL11A1 in colorectal tumors could be associated with the APC/β-catenin pathway in FAP and sporadic colorectal cancer

Differential gene expression profile reveals deregulation of pregnancy specific β1 glycoprotein 9 early during colorectal carcinogenesis

BACKGROUND: APC (Adenomatous polyposis coli) plays an important role in the pathogenesis of both familial and sporadic colorectal cancer. Patients carrying germline APC mutations develop multiple colonic adenomas at younger age and higher frequency than non-carrier cases which indicates that silencing of one APC allele may be sufficient to initiate the transformation process. METHODS: To elucidate the biological dysregulation underlying adenoma formation we examined global gene expression profiles of adenomas and corresponding normal mucosa from an FAP patient. Differential expression of the most significant gene identified in this study was further validated by mRNA in situ hybridization, reverse transcriptase PCR and Northern blotting in different sets of adenomas, tumours and cancer cell lines. RESULTS: Eighty four genes were differentially expressed between all adenomas and corresponding normal mucosa, while only seven genes showed differential expression within the adenomas. The first group included pregnancy specific β-1 glycoprotein 9 (PSG9) (p < 0.006). PSG9 is a member of the carcinoembryonic antigen (CEA)/PSG family and is produced at high levels during pregnancy, mainly by syncytiotrophoblasts. Further analysis of sporadic and familial colorectal cancer confirmed that PSG9 is ectopically upregulated in vivo by cancer cells. In total, deregulation of PSG9 mRNA was detected in 78% (14/18) of FAP adenomas and 75% (45/60) of sporadic colorectal cancer cases tested. CONCLUSION: Detection of PSG9 expression in adenomas, and at higher levels in FAP cases, indicates that germline APC mutations and defects in Wnt signalling modulate PSG9 expression. Since PSG9 is not found in the non-pregnant adult except in association with cancer, and it appears to be an early molecular event associated with colorectal cancer monitoring of its expression may be useful as a biomarker for the early detection of this disease

Different genetic pathways involved in colorectal cancer

Colorectal cancer (CRC) is one of the three leading causes of cancer mortality worldwide with an incidence of approximately one million cases and a mortality of 500 000 annually. Identification of different pathways involved in tumorigenesis of both familial and sporadic colorectal cancer may led to a major breakthrough in the prevention of this potentially curable disease. It has been reported that HNPCC patients have a better prognosis than sporadic colorectal cancer cases. Approximately 13% of sporadic and >90% of HNPCC tumors show microsatellite instability (MSI). In an attempt to explore if MSI phenotype carries prognostic information, we examined 181 sporadic cases using microsatellite markers. No correlation between MSI status and age or gender was found. Survival analysis at 5-10 years follow-up showed a weak favorable clinical course for MSI positive cases. However, the differences in prognosis between microsatellite stable and -unstable cases was not statistically significant. These results indicate that MSI phenotype as such is not an independent prognostic factor. We also searched for other differences between MSI positive and -negative sporadic colorectal tumors. The possibility that these two types of tumors may evolve through different turnorigenesis pathways, were tested by studying the frequency of different gene alterations in MSI and MSS (microsatellite stable) tumors. The prevalence of mutation in the APC, KRAS, TP53, (beta)-catenin and TGF(beta)R2 known to be involved in CRC tumor development was examined using different techniques. A high frequency of MSS tumors showed mutations in the TGF(beta)R2, whereas none of the MSS tumors did. A highly statistically significant negative association was found between MSI and alteration in APC and TP53. Our results strongly support the idea that carcinogenesis in MSI and MSS colorectal cancer develops through different pathways. To find out the best strategy to select mismatch repair gene mutations carrier for further analysis, immunohistochemical testing was compared to MSI test. It was found that Immunohistochemistry could identify most cases with germline mutations in hMLH1 and hMSH2. However, some missense and even truncating mutations will be missed. Cases with hMLH1 promoter methylation will result in false positive results. These results suggested that MSI test is a better method in predicting mismatch repair gene carriers. Inactivating mutations have been found in the cell-cell adhesion molecule E-cadherin in gastric and breast cancer. We searched for E-cadherin alterations in familial gastric and colon cancer. One E-cadherin germline alteration was found in two cases with familial colon and gastric cancer, leading to the substitution of Alanine to Threonine (Ala592Thr). This variant segregates with disease in one family with colon, gastric and breast cancer, although, the penetrance was not complete. A somatic mutation, exon 2 (49-CgA) was also found in a tumor from a patient with familial breast cancer . An allelic association study of the Ala592Thr variant in was performed in a series of cancer cases (colon, breast, gastric). The study did not support the correlation of this variant with an increased risk for breast cancer. However, an association between this alteration and an aggressive phenotype in breast cancer cases was suggested

<it>COL11A1</it> in FAP polyps and in sporadic colorectal tumors

Abstract Background We previously reported that the α-1 chain of type 11 collagen (COL11A1), not normally expressed in the colon, was up-regulated in stromal fibroblasts in most sporadic colorectal carcinomas. Patients with germline mutations in the APC gene show, besides colonic polyposis, symptoms of stromal fibroblast involvement, which could be related to COL11A1 expression. Most colorectal carcinomas are suggested to be a result of an activated Wnt- pathway, most often involving an inactivation of the APC gene or activation of β-catenin. Methods We used normal and polyp tissue samples from one FAP patient and a set of 37 sporadic colorectal carcinomas to find out if the up-regulation of COL11A1 was associated with an active APC/β-catenin pathway. Results In this study we found a statistically significant difference in COL11A1 expression between normal tissue and adenomas from one FAP patient, and all adenomas gave evidence for an active APC/β-catenin pathway. An active Wnt pathway has been suggested to involve stromal expression of WISP-1. We found a strong correlation between WISP-1 and COL11A1 expression in sporadic carcinomas. Conclusions Our results suggest that expression of COL11A1 in colorectal tumors could be associated with the APC/β-catenin pathway in FAP and sporadic colorectal cancer.</p

CDH1 mutations are present in both ductal and lobular breast cancer, but promoter allelic variants show no detectable breast cancer risk

Mutations and diminished expression of the E-cadherin gene (CDH1) have been identified in a number of epithelial malignancies. Although somatic CDH1 mutations were detected in lobular breast cancer with a frequency ranging from 10-56%, CDH1 alterations in more frequent ductal tumors appear to be rare. Here we have analyzed the coding region of CDH1 for mutations using denaturing high performance liquid chromatography and found 4 mutations in 83 ductal carcinomas (5%) and 3 mutations in 25 lobular carcinomas (12%). The germline of 13 patients with familial lobular tumors was also analyzed for mutations, but none were detected. In a case-control study, we also tested whether a variant adenine allele in the promoter polymorphism -161C--&gt;A with a putative influence on the transcriptional activity of CDH1 in vitro confers any detectable risk of breast cancer. No significant difference in the allelic frequency between patients with breast cancer (326/1,152, 28.3%) and controls (190/696, 27.3%, p &gt; 0.05; relative risk 1.05, 95% confidence interval 0.85-1.30) was found. A novel promoter polymorphism was identified at position -152, but the frequency of the variant cytosine allele was also similar in patients with breast cancer and controls (0.71% vs. 0.21%, p = 0.23). Transient transfection experiments using reporter constructs containing the nucleotide substitutions -161C/-152C and -161A/-152T showed only a slight decrease in the transcription activity compared to the wild-type construct. These results do not support CDH1 as a prominent low-penetrance cancer susceptibility gene, but indicate that CDH1 mutations contribute to the progression of both lobular and ductal tumor

Low frequency of E-cadherin alterations in familial breast cancer

In order to explore the possible role of E-cadherin in familial cancer, 19 familial breast cancer patients, whose tumours demonstrated loss of heterozygosity (LOH) at the E-cadherin locus, were screened for germline mutations. No pathogenic germline alterations were detected in these individuals. However, a somatic mutation was found (49-2A?C) in one of the tumours. This tumour showed a pattern of both ductal and lobular histology. Another 10 families with cases of breast, gastric and colon cancer were also screened for germline mutations, and no mutations were found. A missense mutation in exon 12 of E-cadherin (1774G?A; Ala592Thr) was previously found in one family with diffuse gastric cancer, and colon and breast cancer. An allelic association study was performed to determine whether the Ala592Thr alteration predisposes to breast cancer. In total, we studied 484 familial breast cancer patients, 614 sporadic breast cancer patients and 497 control individuals. The frequencies of this alteration were similar in these groups. However, a correlation between the Ala592Thr alteration and ductal comedo-type tumour was seen. These results, together with previously reported studies, indicate that germline mutations and, more commonly, somatic mutations in E-cadherin may have an influence on the behaviour of the tumours, rather than predispose to breast cancer