Preferential loss of maternal alleles in sporadic Wilms' tumour

Loss of heterozygosity at loci on the short arm of chromosome 11 has been reported in 31% (11/38) of Wilms' tumours in our series. Lymphoblastoid cell lines were prepared from the parents of 10/11 of the patients showing allele loss in their tumours. In 9 of the cases, where the parental origin of the alleles could be followed, it was the paternal alleles which were retained in the tumour. This preferential loss of the maternal alleles implies a role for genomic imprinting in the pathogenesis of Wilms' tumour.     

Chromosome 5 allele loss in familial and sporadic colorectal adenomas

DNA extracted from familial and sporadic colorectal neoplasms was compared with constitutional DNA using a range of hypervariable locus specific probes to assess the extent of allele loss during conversion to malignancy. Chromosome 5 allele loss was observed in 23% of carcinoma samples, as previously found by others. However, we have been able to show for the first time loss of the D5S43 locus on chromosome 5 in adenomas from three patients, two of whom had the precancerous condition adenomatous polyposis coli (APC). These results suggest significant genetic changes involving chromosome 5 are occurring in benign adenomas. Probes for chromosome 1 (loci D1S7 and D1S8) and for chromosome 7 (loci D7S21 and D7S22) revealed no notable alterations in the adenoma samples. Complete loss of alleles for loci on chromosome 7 was not observed in carcinomas but reduced intensity of one parental allele was found in three specimens one of which was known to have multiple copies of this chromosome. Results using probes for chromosome 1 suggest that deletion of the D1S7 or D1S8 loci is not a common event in colorectal carcinogenesis. Loss of chromosome 5 alleles in adenomas from APC patients provides evidence in support of Knudson's hypothesis.     

Allelic loss on chromosome 11 in hereditary and sporadic tumors related to familial multiple endocrine neoplasia type 1.

Familial multiple endocrine neoplasia type 1 (FMEN1) is an autosomal dominant disorder characterized by tumors of the parathyroid glands, pancreatic islets, and anterior pituitary. The gene for this disease maps to chromosome 11q12-11q13, and allelic loss in this region has been shown in both sporadic and FMEN1-related parathyroid tumors. FMEN1-related pancreatic islet tumors, and rarely in sporadic anterior pituitary tumors. We tested for allelic loss at 7 loci on chromosome 11 in 17 tumors outside the parathyroid. We found loss of heterozygosity in 2 of 2 FMEN1-related benign pancreatic islet tumors but in none of 8 informative sporadic islet tumors (P = 0.02) including 5 malignant gastrinomas. Of 3 islet tumors from patients who had some but not all features of FMEN1, one showed allelic loss for 5 of 5 informative restriction fragment length polymorphisms, and the other 2 retained heterozygosity for all informative markers. A bronchial carcinoid from an FMEN1 patient and 3 sporadic anterior pituitary tumors showed no allelic loss. These data provide new evidence that many sporadic pancreatic islet neoplasms, even when malignant, do not develop through homozygous inactivation of the MEN1 gene.     

Multiple primary malignancies in patients with sporadic pancreatic endocrine tumors

BACKGROUND: To investigate the appearance of multiple primary malignancies in patients with sporadic neuroendocrine pancreatic tumors (NEPTs). METHODS: One hundred forty-five patients with NEPTs were treated at the Department of Surgery, Philipps-University Marburg. Multiple primary malignancies included tumors that were not considered to be a metastasis, invasion, or recurrence of NEPTs. Data on sex, age at diagnosis of cancer, follow-up time after diagnosis, and death rate were collected. RESULTS: Of 115 patients with sporadic NEPTs, 15 (13.0%) patients were identified with at least one malignant tumor, other than a NEPT. The median age at diagnosis of the associated tumor(s) was 57 years (range, 10-72 years). Two of the 15 patients had insulinomas, 5 had gastrinomas and 8 had non-functioning NEPTs, respectively. The risk of developing multiple cancers was the highest for patients with gastrinoma (21.7%), followed by patients with non-functioning NFPTs (20.5%). CONCLUSIONS: In patients with NEPTs multiple primary malignancies are found more frequently than in the general population. The etiology of the increased risk of other primaries is not clearly defined, but it may be the result of accumulated growth stimulation by the secreted hormones or a genetic alteration that leads to tumorogenesis in these patients.     

Identification of somatic mutations of the MEN1 gene in sporadic endocrine tumours

Endocrine tumours of the pancreas, anterior pituitary or parathyroids arise either sporadically in the general population, or as a part of inherited syndromes such as multiple endocrine neoplasia type 1 (MEN 1). The mechanisms responsible for the development of sporadic endocrine lesions are not well understood, although loss of heterozygosity (LOH) of the MEN1 locus on chromosome 11q13 and somatic mutation of the MEN1 gene have been frequently associated with the development of MEN 1-type sporadic endocrine lesions. To further investigate the role of the MEN1 gene in sporadic endocrine tumorigenesis, we analysed DNA from 14 primary parathyroid lesions, 8 anterior pituitary tumours and 3 pancreatic tumours for the presence of somatic MEN1 gene mutations and LOH of seven microsatellite markers flanking the MEN1 locus. In addition, we similarly analysed 8 secondary parathyroid lesions which arose in patients with chronic renal failure. None of the patients studied had a family history of MEN 1. Three primary parathyroid lesions and one pancreatic tumour (glucagonoma) were found to have lost one allele at the MEN1 locus. Somatic mutations were identified by SSCP and sequence analysis in one of these parathyroid lesions (P320L) and in the glucagonoma (E179V). These results support previous findings that inactivation of the MEN1 tumour suppressor gene contributes to the development of sporadic MEN 1-type endocrine lesions but is not associated with the development of parathyroid hyperplasia seen in some renal failure patients.     

C-ERB-B2/INT-2 amplification appears faster in breast-cancer patients receiving second-line endocrine treatment

We have examined the appearance of c-erb-b2 and int-2 amplification in 2 different groups of breast-cancer patients. The groups differed with regard to their clinical status in that one group was receiving first-line endocrine treatment (tamoxifen) whereas the second was receiving second-line endocrine treatment (after failing on tamoxifen). The latter group of patients showed clinically a more advanced disease (higher frequency of stage-IV as compared to stage-III disease). Consecutive tumor samples were obtained using fine-needle biopsies from individual tumor lesions of each patient every second or third month. Median time from diagnosis to the last biopsy for patients receiving tamoxifen was 25 months and, for patients receiving second-line treatment, 55 months. The presence of amplification was determined using semi-quantificative PCR. We found that both genes developed amplification during tumor progression. The appearance of amplification was more pronounced in the clinically more advanced patients receiving second-line treatment (p = 0.018). © 1996 Wiley-Liss, Inc.     

Microsatellite instability and mismatch repair gene inactivation in sporadic pancreatic and colon tumours.

Genomic instability has been proposed as a new mechanism of carcinogenesis involved in hereditary non-polyposis colorectal cancer (HNPCC) and in a large number of sporadic cancers like pancreatic and colon tumours. Mutations in human mismatch repair genes have been found in HNPCC patients, but their involvement in sporadic cancer has not been clarified yet. In this study we screened 21 pancreatic and 23 colorectal sporadic cancers for microsatellite instability by ten and six different microsatellite markers respectively. Microsatellite alterations were observed at one or more loci in 66.6% (14/21) of pancreatic cancers and in 26% (6/23) colon tumours, but all the pancreatic and half of the colon samples showed a low rate of microsatellite instability. All the unstable samples were further analysed for mutations in the hMLH1 and hMSH2 genes and for hypermethylation of the hMLH1 promoter region. Alterations in the hMLH1 gene were found only in colorectal tumours with a large presence of microsatellite instability. None of the pancreatic tumours showed any alteration in the two genes analysed. Our results demonstrate that microsatellite instability is unlikely to play a role in the tumorigenesis of sporadic pancreatic cancers and confirm the presence of mismatch repair gene alterations only in sporadic colon tumours with a highly unstable phenotype.     

APC gene mutations and allelic losses in sporadic ampullary tumours: Evidence of genetic difference from tumours associated with familial adenomatous polyposis

We explored APC gene mutations and chromosome 5q21 allelic losses (5qLOH) in 18 neoplasms of the papilla of Vater, including 6 early-stage tumours (3 adenomas, 3 carcinomas) and 12 advanced-stage cancers. Eleven PCR-amplified polymorphic sequences were used to analyse 5qLOH. APC mutations were investigated both by an in vitro APC-protein truncation test and by single-strand conformation polymorphism analysis. Mutations in the Ki-ras, N-ras and p53 genes were also assessed. We found: 5qLOH in 8 of 16 cases (50%), including 1 adenoma, 3 early- and 4 advanced-stage cancers; APC mutations in 2 adenomas and 1 advanced-stage carcinoma; Ki- or N-ras mutations in 3 adenomas and 3 advanced-stage cancers; p53 mutations in 2 early-stage and 7 advanced-stage adenocarcinomas. Our results suggest that 5qLOH, APC mutations and ras mutations are present at early stages, whereas p53 inactivation is associated with progression of malignancy in a large proportion of cases. These data indicate that sporadic ampullary tumours differ from those occurring in familial adenomatous polyposis in the frequency (17% vs. 64%) as well as in the site of APC somatic mutations, suggesting a different molecular pathogenesis in the 2 conditions. © 1996 Wiley-Liss, Inc.     

Polymorphisms of SPINK1 N34S and CFTR in patients with sporadic and familial pancreatic cancer

Long standing chronic pancreatitis is a risk factor for developing pancreatic cancer. Inheritance of polymorphisms in SPINK1 and CFTR are associated with an increased risk of developing pancreatitis. The aim of this study was to determine if patients who carry polymorphisms in SPINK1 and CFTR are at increased risk of developing pancreatic cancer through the development of chronic pancreatitis. DNA from patients with histologically-confirmed surgically-treated chronic pancreatitis, familial and sporadic pancreatic adenocarcinoma and controls were analyzed for the N34S polymorphism of SPINK1 and the two commonest polymorphisms of the CFTR gene, the DF508 mutation and the 5T polymorphism. These polymorphisms were determined using restriction fragment length polymorphism, PCR and cycle sequencing methods. The SPINK1 N34S polymorphism was detected in 5 of 172 (2.9%) patients with chronic pancreatitis, in 4 of 200 (2.0%) patients with sporadic pancreatic adenocarcinoma, in 0 of 36 (0%) of patients with familial pancreatic cancer and in 3 of 177 (1.7%) controls of chronic cholecystitis. The CFTR 5T polymorphism was identified in 31 of 334 (9.3%) patients of sporadic pancreatic cancer, in 5 of 43 (11.6%) patients with familial pancreatic cancer and in 10 of 112 (8.9%) controls with colorectal cancer. The CFTR DF508 mutation was recognized in 6 of the 240 (2.5%) patients with pancreatic adenocarcinoma, a prevalence similar to that of control populations. We conclude that the N34S polymorphism of SPINK1 and the 5T and DF508 CFTR polymorphisms do not predispose to the development of pancreatic adenocarcinoma. Furthermore, the N34S polymorphism is rarely found in patients with severe idiopathic chronic pancreatitis.     

Gastrinoma: sporadic and familial disease

The physiologic sequelae of a gastrinoma can be well controlled with medical therapy. The role of surgery has shifted from managing acid hyper-secretion and ulcer complications to preventing metastatic disease and managing symptomatic metastases. With improved methods of imaging for the detection of occult gastrinomas, the prospective evaluation of the role for surgery in altering the natural history of these tumors is now possible.     

PALB2 mutations in familial breast and pancreatic cancer

PALB2 (Partner And Localizer of BRCA2) binds to and co-localizes with BRCA2 in DNA repair. Germline mutations in PALB2 have been identified in approximately 1–2% of familial breast cancer and 3–4% of familial pancreatic cancer cases. The goal of this study was to evaluate the prevalence of PALB2 mutations in women with breast cancer without BRCA1/2 mutations who also had a personal or family history of pancreatic cancer. PALB2 mutation analysis was performed in 94 non-BRCA1/2 breast cancer patients with a personal or family history of pancreatic cancer. Two truncating PALB2 mutations, c.3549C>CA and c.2962C>CT, were identified resulting in a mutation prevalence of 2.1%. The proband found to carry the c.3549C>CA PALB2 mutation had a mother diagnosed with both breast and pancreatic cancer; this relative was subsequently confirmed to carry the identical mutation. The proband with the c.2962C>CT mutation had a father and paternal aunt diagnosed with pancreatic cancer; neither relative was available for testing. Two novel PALB2 missense variants were also found, one of which was deemed potentially deleterious. The prevalence rate of PALB2 mutations in a non-BRCA1/2 breast cancer population specifically selected for a family history of pancreatic cancer does not appear to be significantly increased compared to that observed in other breast cancer populations studied thus far. Further evaluation is needed to determine the prevalence of PALB2 mutations and the clinical utility of such testing in those individuals affected with both breast and pancreatic cancers.     

ATM mutations in sporadic lymphoid tumours

Patients with the autosomal recessive disorder ataxia telangiectasia (A-T) show the biallelic inactivation of the ataxia telangiectasia mutated (ATM) gene. A-T patients exhibit a predisposition to the development of a wide range of lymphoid tumours, suggesting that the ATM protein normally plays an important role in the prevention of both T and B cell malignancies. The ATM protein is a 370 kDa protein kinase implicated in the integration of different cellular responses to particular forms of DNA damage. Several recent studies have reported the possibility that the ATM gene can act as a tumour suppressor gene in non A-T individuals. Frequent ATM inactivation was confirmed in three sporadic lymphoid tumours of mature phenotype: T cell prolymphocytic leukaemia (T-PLL), B-cell chronic lymphocytic leukaemia (B-CLL) and mantle cell lymphoma (MCL). Here, we provide a summary of the published ATM mutations in sporadic lymphoid tumours, including our own study on the role of ATM mutations in the pathogenesis of sporadic B-CLL. The published results suggest possible differences in the origin, the nature and distribution of ATM mutations between sporadic B-CLL, MCL and T-PLL. While ATM mutations in mature B cell tumours (B-CLL and MCL) represent a mixture of missense and truncating errors distributed across the whole of the ATM coding sequence, mutations in sporadic T-PLL appear to be predominantly missense, clustering in the region encoding the PI-3 kinase catalytic domain of the protein. The reason for this difference is unclear, but the difference itself supports the notion that the pathogenesis of B and T cell tumours on an ATM deficient background might be different. In addition, in both B-CLL and MCL ATM mutation carriers have been reported, raising the possibility that ATM mutation carriers may have an increased risk of developing these tumours. The existence as well as magnitude of the risk, however, remains to be established. Furthermore, our own studies indicate that the presence of ATM mutations in sporadic B-CLL causes a distinctive defect in response to DNA damaging agents, offering a possible explanation for the poor response of ATM mutant tumours to standard treatment. Therefore, one of the future challenges will be to devise strategies to bypass the existing defect in response to DNA damage and activate apoptosis in ATM mutant sporadic lymphoid tumours.     

BRCA2 germline mutations in familial pancreatic carcinoma

BACKGROUND: Although as many as 10% of pancreatic cancer cases may have an inherited component, familial pancreatic cancer has not been linked to defects in any specific gene. Some studies have shown that families with germline mutations in the breast cancer susceptibility gene BRCA2 have an increased risk of breast and ovarian cancers, as well as a modestly increased risk of pancreatic cancer. To study these relationships in more detail, we examined whether BRCA2 germline mutations are associated with familial pancreatic cancer. METHODS: We identified 26 European families in which at least two first-degree relatives had a histologically confirmed diagnosis of pancreatic ductal adenocarcinoma. We sequenced genomic DNA isolated from peripheral blood lymphocytes obtained from participating family members to identify germline mutations in BRCA2. RESULTS: Three (12%, exact 95% confidence interval [CI] = 2% to 30%) families carried germline frameshift mutations in the BRCA2 gene that are predicted to result in a truncated BRCA2 protein. Two additional families harbored mutations previously designated as unclassified variants of BRCA2. Thus, 19% (exact 95% CI = 7% to 39%) of the families in our study had either a frameshift mutation or an unclassified variant of BRCA2. None of the families in our study met the criteria for familial breast or ovarian cancer. CONCLUSIONS: Our data support an important role for BRCA2 germline mutations in a subpopulation of families with familial pancreatic cancer. BRCA2 mutation analysis should be included in molecular genetic testing and counseling strategies in families with at least two first-degree relatives affected with ductal adenocarcinoma of the pancreas.     

HLA antigens in familial and sporadic cutaneous melanoma

One hundred and twenty-four subjects belonging to 25 families, 51 with familial malignant melanoma (FMM), and 186 subjects belonging to 41 families, 41 with sporadic malignant melanoma, were typed for the HLA A, B, C and DR loci of the HLA system. There was the same statistically significant difference in the frequency of the haplotype A9, B35, Cw4 between each group of patients and the respective healthy relatives (p = 0.01, p = 0.01 and p = 4 x 10(-3), respectively). Moreover, the higher frequency of the haplotype A9, B35, Cw4 in the healthy members of the FMM families (42.46%) compared with the healthy members of the SMM families (23.44%) indicates that in the latter group other individuals are at risk for the disease. Furthermore, the different frequency of haplotypes B5, DR5 and B5, Cw1 suggest that differences exist between the two groups of healthy relatives. These observations confirm that the HLA region is involved in the etiology of malignant melanoma.     

家族性与散发性乳腺癌BRCA1与FANCD2基因相关性的研究

目的:探讨乳腺癌组织BRCA1与FANCD2基因表达,明确BRCA1基因与FANCD2基因之间的相关性.方法:选取104例乳腺癌手术标本,其中家族性乳腺癌52例,散发性乳腺癌52例.采用SP免疫组化法检测BRCA1和FANCD2在家族和散发性乳腺癌组织中的表达.结果:在家族性乳腺癌组织中,BRCA1蛋白阳性表达37例(71.2％),FANCD2蛋白阳性表达18例(34.6％),两组差异有统计学意义,P＜0.05.在散发性乳腺癌组织中,BRCA1蛋白阳性表达19例(36.5％),FANCD2蛋白阳性表达27例(51.9％),两组差异无统计学意义.结论:BRCA1和FANCD2基因表达与乳腺癌的发生和发展存在一定相关性,FANCONI/BRCA 通路的抑制,可能是乳腺癌,尤其是家族性乳腺癌发生发展以及形成的原因之一.