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Background/aims: LKB1 is a tumour suppressor gene that is associated with Peutz-Jeghers syndrome (PJS), a rare autosomal dominant cancer predisposition syndrome. However, germline mutations in the LKB1 gene are found in only about 60% of patients with PJS, suggesting the existence of a second PJS gene. The STRAD gene, encoding an LKB1 interacting protein that activates LKB1, which subsequently leads to polarisation of cells, is an interesting candidate for a second PJS gene and a potential tumour suppressor gene in sporadic carcinomas., Methods: The involvement of STRAD in 42 PJS associated tumours (sporadic lung, colon, gastric, and ovarian adenocarcinomas) was studied using loss of heterozygosity (LOH) analysis of eight microsatellite markers on chromosome 17, including TP53, BRCA1, and STRAD markers., Results: Loss of the marker near the STRAD locus was seen in 13 of 29 informative cases, including all gastric adenocarcinomas. Specific LOH of the STRAD marker was found in four of 29 informative cases. For these patients all exons and exon-intron boundaries of the STRAD gene were sequenced, but no somatic mutations were identified. Furthermore, no germline STRAD mutations were found in 10 patients with PJS and family members without LKB1 germline mutation., Conclusions: Despite the frequent occurrence of LOH in the STRAD region, these results indicate that inactivation of the STRAD gene is not essential in the sporadic adenocarcinomas studied, although it is possible that STRAD may be inactivated in different ways. In addition, no evidence was found for the hypothesis that STRAD is a second PJS susceptibility gene.

Aims: To investigate the occurrence of preinvasive neoplastic lesions in ovarian surface epithelium and ovarian inclusion cyst epithelium of women with a hereditary predisposition to the development of female adnexal (ovarian and fallopian tube) carcinoma and to assess the expression of differentiation and proliferation related proteins within putative sites of origin of serous ovarian carcinoma, the ovarian surface epithelium and ovarian inclusion cyst epithelium., Methods: Twenty-one ovaries, prophylactically removed from 11 women predisposed to the development of female adnexal cancer (cases) were compared with 22 ovaries from 11 women without such predisposition (controls). Archival histological specimens were screened for hyperplastic and dysplastic epithelial lesions. In both the ovarian surface and inclusion cyst epithelia, the percentage of cells was determined that stained positively for Ki67, p21, p27, p53, cyclin A, cyclin D1, bcl-2 and the presence of HER-2/neu, oestrogen (ER-alpha) and progesterone receptors (PR)., Results: No preinvasive neoplastic lesions were detected. However, hyperplastic areas were found in three cases and in four controls (NS). ER-alpha (P = 0.013), PR (P < 0.001), bcl-2 (P = 0.008), p21 (P = 0.046) and p27 (P = 0.008) were expressed in a significantly higher percentage of cells in inclusion cyst epithelium than in ovarian surface epithelium (both groups). The latter showed higher bcl-2 expression in cases (P = 0.05) compared with controls. The inclusion cyst epithelium of cases showed higher expression of bcl-2 (P = 0.006) and PR (P = 0.039) compared with controls. Proliferation was low in both cases and controls as reflected by low Ki67 expression. Over-expression of p53, cyclin D1 and HER-2/neu was not detected., Conclusions: Premalignant changes are not a common feature of ovaries removed prophylactically from women predisposed to the development of female adnexal carcinoma. Increased expression of p21, p27, and ER-alpha is seen in inclusion cyst compared with ovarian surface epithelium of women with and without an inherited risk of adnexal carcinoma. This is most probably caused by the different intraovarian hormonal milieu of inclusion cyst epithelium. However, the increased expression of bcl-2 and PR in the inclusion cyst epithelium of patients with a hereditary predisposition may reflect early disruption of hormonal balance and growth control.

The two most common inherited forms of colorectal cancer are familial adenomatous polyposis and hereditary non-polyposis colorectal cancer. Simultaneous inheritance of both an APC gene mutation and a mismatch repair gene (for example, MLH1) mutation has never been described. In the present case report, we report rapidly progressive adenomatous polyposis in a 10 year old boy with a germline frame shift mutation in the APC gene and a germline splice site mutation in the MLH1 gene. Immunohistochemical investigations showed abnormal expression of beta-catenin in early adenomas with low grade dysplasia, attributed to the APC gene mutation. Subsequent loss of function of the MLH1 gene, as shown by absent immunostaining of its protein in adenomas with high grade dysplasia, may well have caused the rapid progression to high grade dysplasia in many of the adenomas.

Hereditary non-polyposis colorectal cancer is an autosomal dominant condition due to germline mutations in DNA-mismatch-repair genes, in particular MLH1, MSH2 and MSH6. Here we describe the application of a novel technique for the detection of genomic deletions in MLH1 and MSH2. This method, called multiplex ligation-dependent probe amplification, is a quantitative multiplex PCR approach to determine the relative copy number of each MLH1 and MSH2 exon. Mutation screening of genes was performed in 126 colorectal cancer families selected on the basis of clinical criteria and in addition, for a subset of families, the presence of microsatellite instability (MSI-high) in tumours. Thirty-eight germline mutations were detected in 37 (29.4%) of these kindreds, 31 of which have a predicted pathogenic effect. Among families with MSI-high tumours 65.7% harboured germline gene defects. Genomic deletions accounted for 54.8% of the pathogenic mutations. A complete deletion of the MLH1 gene was detected in two families. The multiplex ligation-dependent probe amplification approach is a rapid method for the detection of genomic deletions in MLH1 and MSH2. In addition, it reveals alterations that might escape detection using conventional diagnostic techniques. Multiplex ligation-dependent probe amplification might be considered as an early step in the molecular diagnosis of hereditary non-polyposis colorectal cancer., (Copyright 2002 Cancer Research UK)

Purpose: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease characterized by the clustering of colorectal cancer, endometrial cancer, and various other cancers. The disease is caused by mutations in DNA-mismatch-repair (MMR) genes, most frequently in MLH1, MSH2, and MSH6. The aims of the present study were to compare the risk of developing colorectal, endometrial, and other cancers between families with the various MMR-gene mutations., Patients and Methods: Clinical and pathologic data were collected from 138 families with HNPCC. Mutation analyses were performed for all families. Survival analysis was used to calculate the cumulative risk of developing cancer in the various subsets of relatives., Results: Mutations were identified in 79 families: 34 in MLH1, 40 in MSH2, and five in MSH6. The lifetime risk of developing cancer at any site was significantly higher for MSH2 mutation carriers than for MLH1 mutation carriers (P < .01). The risk of developing colorectal or endometrial cancer was higher in MSH2 mutation carriers than in MLH1 mutation carriers, but the difference was not significant (P = .13 and P = .057, respectively). MSH2 mutation carriers were found to have a significantly higher risk of developing cancer of the urinary tract (P < .05). The risk of developing cancer of the ovaries, stomach, and brain was also higher in the MSH2 mutation carriers than in the MLH1 mutation carriers, but the difference was not statistically significant., Conclusion: Pending large prospective studies, the extension of the current surveillance program in MSH2 mutation carriers with the inclusion of the urinary tract should be considered.

Background: Mutations in the BRCA1 or BRCA2 genes are responsible for up to 95% of hereditary ovarian cancer cases. Both genes function as tumour suppressor genes, and development of a cancer is thought to require an accumulation of somatic genetic events in addition to the inherited germline predisposition. It is unknown whether these somatic events in BRCA associated ovarian cancer are similar to or distinct from those in sporadic cases. The most frequent somatic genetic event in ovarian cancer is a mutation of the p53 gene., Aim: To study the role of p53 in hereditary ovarian cancer, by analysing accumulation of the p53 protein in ovarian cancers which occurred in BRCA1 or BRCA2 germline mutation carriers and comparing the results with a panel of ovarian cancers from patients who tested negative for both BRCA1 and BRCA2., Methods: The study group consisted of 39 ovarian cancer patients in whom a BRCA mutation had been confirmed previously. p53 Immunohistochemistry was performed on archival tissue using a standard microwave antigen retrieval technique. The rate of p53 accumulation was compared with 40 ovarian cancer cases who tested negative for BRCA1 and BRCA2 germline mutations., Results: P53 Accumulation was similar in BRCA related ovarian cancers and BRCA negative controls. Overall 27 of 39 BRCA1 or BRCA2 positive cases (69%) had evidence of p53 accumulation, compared with 24 of 40 invasive ovarian cancer cases (60%) which tested negative for BRCA1 and BRCA2 germline mutations. BRCA1 related ovarian cancers showed p53 accumulation in 22 of 30 cases (73%); p53 accumulation was present in five of nine BRCA2 related ovarian cancers., Conclusions: In addition to germline BRCA1 and BRCA2 mutations, somatic p53 alterations leading to p53 accumulation are an important event in hereditary ovarian cancer and are as frequent as in non-BRCA-related ovarian cancer.

For families with a small number of cases of breast and/or ovarian cancer, limited data are available to predict the likelihood of genetic predisposition due to mutations in BRCA1 or BRCA2. In 104 families with three or more affected individuals (average 3.8) seeking counselling at family cancer clinics, mutation analysis was performed in the open reading frame of BRCA1 and BRCA2 by the protein truncation test and mutation-specific assays. In 31 of the 104 families tested, mutations were detected (30%). The majority of these mutations (25) occurred in BRCA1. Mutations were detected in 15 out of 25 families (60%) with both breast and ovarian cancer and in 16 out of 79 families (20%) with exclusively cases of breast cancer. Thus, an ovarian cancer case strongly predicted finding a mutation (P < 0.001). Within the group of small breast-cancer-only families, a bilateral breast cancer case or a unilateral breast cancer case diagnosed before age 40 independently predicted finding a BRCA1 or BRCA2 mutation (P = 0.005 and P = 0.02, respectively). Therefore, even small breast/ovarian cancer families with at least one case of ovarian cancer, bilateral breast cancer, or a case of breast cancer diagnosed before age 40, should be referred for mutation screening.

We searched for criteria that could indicate breast cancer families with a high prior probability of being caused by the breast/ovarian cancer susceptibility locus BRCA1 on chromosome 17. To this end, we performed a linkage study with 59 consecutively collected Dutch breast cancer families, including 16 with at least one case of ovarian cancer. We used an intake cut-off of at least three first-degree relatives with breast and/or ovarian cancer at any age. Significant evidence for linkage was found only among the 13 breast cancer families with a mean age at diagnosis of less than 45 years. An unexpectedly low proportion of the breast-ovarian cancer families were estimated to be linked to BRCA1, which could be due to a founder effect in the Dutch population. Given the expected logistical problems in clinical management now that BRCA1 has been identified, we propose an interim period in which only families with a strong positive family history for early onset breast and/or ovarian cancer will be offered BRCA1 mutation testing.