PubMed Health⌕ Search

Biomedical subjects

Xavier Matias-Guiu

Publications and source records attributed to Xavier Matias-Guiu.

25 records · Page 2Linked to original sources
PubMed2002

Microsatellite instability and immunostaining for MSH-2 and MLH-1 in cutaneous and internal tumors from patients with the Muir-Torre syndrome.

BACKGROUND: Muir-Torre syndrome (MTS) is characterized by the co-existence of sebaceous gland tumors of the skin and internal malignancies. Currently, MTS is regarded as a variant of the hereditary non-polyposis colon cancer syndrome (HNPCC). Both MTS and HNPCC are secondary to germline mutations in DNA mismatch repair genes (mainly MSH-2 and MLH-1). METHODS: Cutaneous (eight sebaceous adenomas, one sebaceous carcinoma and one keratoacanthoma) and internal tumors (four colonic adenocarcinomas, two endometrial carcinomas, two transitional cell carcinomas of renal pelvis and ureter, one adenocarcinoma of the small bowel, one ovarian carcinoma and one colonic tubular adenoma) were obtained from six patients with MTS and were subjected to microsatellite instability (MI) analysis, and to immunostaining for MLH-1 and MSH-2. MI was assessed by evaluating three (CA)n dinucleotide repeats (D2S123, D5S346, D17S250) and the mononucleotide tracts BAT 26 and BAT 25. RESULTS: All cutaneous and internal tumors exhibited MI. An immunohistochemical concordance between all tumors within each single patient was obtained in five cases. In these five patients all tumors exhibited a lack of MSH-2 staining, consistent with a germline abnormality in this gene. In the one remaining case, the immunohistochemical staining in the sebaceous adenoma was negative for MLH-1 and positive for MSH-2, consistent with a germline alteration in MLH-1. However, the colonic adenocarcinoma in that patient showed positivity for MSH-2 and an equivocal positivity for MLH-1. CONCLUSIONS: The results confirm that tumors from patients with MTS exhibit MI. Moreover, immunostaining for MLH-1 and MSH-2 may be useful to identify the most probable gene responsible for the disease in each family.

Adaptor Proteins, Signal Transducing↗
PubMed2002

PTEN mutations in eight Spanish families and one Brazilian family with Cowden syndrome.

Cowden syndrome is an autosomal dominant genodermatosis, characterized by the presence of multiple hamartomas in the skin, breast, thyroid, gastrointestinal tract, central nervous system, and an increased risk in developing breast and thyroid carcinomas. Over 80 germline mutations of the tumor suppressor gene PTEN, on chromosome 10q23, have been reported in more than 100 unrelated patients and families; however, questions regarding distribution of the mutations in populations from different geographic areas, and phenotypic expression are still unclear. In this study the results are reported of mutation analysis of PTEN in 13 families from Spain and one family of Brazilian origin with Cowden syndrome. PTEN germline mutations were detected in nine of them (64%). Five mutations were located in exon 5, one in exon 6, two in exon 7, and one in exon 8. Four of the mutations were novel. In another case, an identical change had been previously reported as a somatic mutation in an endometrial carcinoma. In one family, the patient presented a de novo mutation, which was not detected in his parents. In five patients, the detection of the PTEN germline mutation confirmed their condition, even in the absence of sufficient criteria to make the clinical diagnosis of Cowden syndrome.

Adolescent↗
PubMed2002

CTNNB1 mutations and beta-catenin expression in endometrial carcinomas.

Mutations in the beta-catenin gene (CTNNB 1) with abnormal nuclear accumulation of beta-catenin have recently been identified in endometrial carcinoma (EC). Their relationship with microsatellite instability (MI) is unclear. It has been suggested that matrix metalloproteinase-7 (MMP-7) and cyclin D1 (cD) genes are targets for beta-catenin activation. DNA from 73 patients with EC was obtained from tumor and normal tissue (59 endometrioid and 14 nonendometrioid). CTNNB 1 mutations in exon 3 were assessed by single-strand conformation polymorphism and DNA sequencing. The results were correlated with immunostaining for beta-catenin, MMP-7, and cD. Three (CA)n repeats and mononucleotide tracts BAT 25 and BAT 26 had been previously used for MI analysis. CTNNB1 mutations were identified in 15 ECs (20.5%), all of them endometrioid carcinomas (15 of 59; 25.4%). They occurred in 6 of 19 MI-positive ECs (31.5%) and in 9 of 54 MI-negative ECs (16.6%). Eleven of the 15 CTNNB 1-mutated ECs showed beta-catenin nuclear immunostaining (P <.05). MMP-7 expression (>50% cells) was observed in 23 ECs, with 7 of these showing CTNNB 1 mutations. Significant expression of cD (>50% cells) was detected in 8 ECs, with 5 of these exhibiting CTNNB 1 mutations (P <.05). The results confirm that beta-catenin plays a role in endometrial carcinogenesis, particularly in endometrioid carcinomas. The results also suggest that MMP-7 and particularly cD may be targets of beta-catenin activation in ECs.

Adenocarcinoma↗
PubMed1998

Renal Cell Carcinoma Metastatic to the Thyroid Gland: A Comparative Molecular Study Between the Primary and the Metastatic Tumor.

A case of renal cell carcinoma metastatic to the thyroid gland is presented. The thyroid tumor showed typical features: clear cells arranged in nests with a prominent sinusoidal vascular pattern. The histologic appearance was identical to the renal tumor removed 6 yr before. A comparative molecular study between the primary and the metastatic tumor showed a common profile with a loss of heterozygosity at identical loci on chromosome 3, which provided further support to the metastatic nature of the thyroid tumor. However, the frequent existence of allele losses on chromosome 3p in both renal cell carcinomas and primary thyroid follicular carcinomas rest some force from such a molecular approach to the differential diagnosis of thyroid tumors that contain a predominant population of clear cells.

Journal Article↗
PubMed1995

Molecular Diagnosis of Multiple Endocrine Neoplasia (MEN) in Paraffin-Embedded Specimens.

In this article, we summarize our recent findings on rearranged during transfection (RE7) mutations in a series of 46 sporadic as well as multiple endocrine neoplasia (MEN) type 2- associated tumors and present results of our family screening efforts to identify MEN 2 and MEN 1 gene carriers. A nonisotopic polymerase chain reaction-based single-strand conformation polymorphism (PCR-SSCP) analysis and heteroduplex gel electrophoresis method was used to screen DNA extracted from archival specimens of 22 patients with MEN 2-associated and 24 patients with sporadic tumors for mutations in RETexons 1O, 11, 13, and 16. Point mutations were identified by nonisotopic cycle sequencing of PCR products using an automated DNA sequencer. We found six different missense germ line mutations at cysteine residues encoded by exons 10 and 11 in all patients with MEN 2A or familial medullary thyroid carcinoma (FMTC). The frequency of mutations at codon 634 was higher in patients with MEN 2A than with FMTC and a (63)Cys - Arg mutation was associated with parathyroid disease. A germline Met -* Thr point mutation at codon 918 of the RETtyrosine kinase domain encoded by exon 16 was identified in all MEN 2B patients. Nonpredicted inheritable medullary thyroid carcinomas (MTCs) were detected in two patients and a mosaic postzygotic mutation was found in one additional patient. Tumor-specific (somatic) Met - Thr point mutations at codon 918 were identified in 5 of 13 sporadic MTCs and 2 of 8 sporadic pheochromocytomas (PCCs). The remaining sporadic tumors lacked mutations in all four RET exons tested. In exon 13, a nucleic acid polymorphism (CTT/CTG; Leu) at codon 769 was identified, which is present in approx 40% of the examined population. Our study demonstrates that the molecular methods used are not only suitable to identify asymptomatic individuals at risk for MEN 2A, FMTC, and MEN 2B, but also to distinguish sporadic from inherited tumors using archival tissue specimens; and that more tumors than clinically expected are inheritable, indicating the need for genetic analysis of all MTC and PCC patients.

Journal Article↗