Sérgio Castedo

Cleft lip/palate and CDH1/E-cadherin mutations in families with hereditary diffuse gastric cancer

We report the association of CDH1/E-cadherin mutations with cleft lip, with or without cleft palate (CLP), in two families with hereditary diffuse gastric cancer (HDGC). In each family, the CDH1 mutation was a splicing mutation generating aberrant transcripts with an in-frame deletion, removing the extracellular cadherin repeat domains involved in cell-cell adhesion. Such transcripts might encode mutant proteins with trans-dominant negative effects. We found that CDH1 is highly expressed at 4 and 5 weeks in the frontonasal prominence, and at 6 weeks in the lateral and medial nasal prominences of human embryos, and is therefore expressed during the critical stages of lip and palate development. These findings suggest that alteration of the E-cadherin pathway can contribute to human clefting.

Cytogenetic investigations of 340 thyroid hyperplasias and adenomas revealing correlations between cytogenetic findings and histology

Cytogenetic analyses were performed on 340 follicular thyroid adenomas and goiters after short-term culture. Clonal chromosomal changes were found in 67 cases. Trisomy 7 as the sole abnormality or along with other trisomies was the most frequent type of aberration (19 cases). Other recurrent numerical changes were loss of chromosome 22 (4 cases) and the second X or the Y chromosome (5 cases). Translocations involving 19q13 (12 cases) were frequent structural chromosomal changes. Dicentric chromosomes or telomeric associations were frequent in goiters (12 cases). After a histopathologic classification of all cases, we have correlated the cytogenetic findings with the histology of the tumors. Only 8.4% of the goiters showed clonal abnormalities, whereas 44.9% of the adenomas revealed clonal abnormalities. Furthermore, simple clonal changes were predominantly found in goiters and complex changes in adenomas. The most impressive correlation was found in the group of lesions with trisomy 7. Although all but one lesion with one or two additional trisomies were goiters, those having three or more additional trisomies were all adenomas or adenomatous goiters.

Frequency of NUP98-NSD1 fusion transcript in childhood acute myeloid leukaemia

residual B-cell clone with the same IgH gene rearrangement as that detected at diagnosis (Figure 1). The patient serum was screened for hepatitis C virus (HCV) mRNA, and was found to be negative. The data herein presented suggest that MVL may predate the SLVL (or SMZL) of some years, as confirmed by the clinical course of two out of the three MVL cases studied, but is also amenable to spontaneous regression. The distinctive feature of the MVL–SLVL complex appears to be an early isolated lymphocytosis, whereas splenomegaly and other lymphomalike symptoms would develop later. In SLVL, splenomegaly is almost always detectable, even without lymphocytosis. How often MVL would precede SLVL and issues of treatment and prognosis are all open questions. We have previously shown MVL cases to express adhesion molecules critical for the function of lymphocyte trafficking. A peculiar expression of these receptors, as described in human SMZL, may favour a bloodstream dissemination without organ involvement, and could help differentiate MVL/SLVL from primary SLVL. Estimating the incidence of MVL is difficult. The diagnosis is primarily based on the careful examination of the peripheral blood film in any patient with a monoclonal B-cell lymphocytosis of undetermined significance, particularly if CD5 . In the French series including 100 SLVL cases, 14 out of 32 patients who never required therapy had an isolated lymphocytosis without splenomegaly, a condition that could match MVL. Another finding that may be typical of MVL is its cyclical behaviour. Cyclical lymphocyte fluctuations are not typical of Bcell leukaemias. It may be argued that activation/suppression of genes regulating the cell cycle, cytokine loops, and cytotoxic T/NK cells may variously affect the proliferative rate of MVL. A fortuitous combination of strongly suppressive effects might occasionally induce a clonal regression (if not an extinction), like the one observed in one patient. The possible regression of SLVL following treatment of hepatitis C virus infection points to the biological instability of these clones and to the critical role of extrinsic factors. The hypothesis is enforced by the results obtained in gastric B-cell lymphoma of marginal immunophenotype after cure of lymphoma-associated Helicobacter pylori infection where clinical but not molecular remissions are achieved. MVL can be regarded as a long-lasting, nonmalignant cellular clonopathy antecedent to the development of SLVL or, due to hitherto unrecognized factors, a transient lymphoproliferative disorder with a potential for a spontaneous and durable clinical regression despite the persistence of the molecular abnormality. It is important to recognize this phase, and to abstain from unnecessary therapeutic intervention.

Cytogenetic findings in eleven gastric carcinomas

We describe the results of the cytogenetic study of 10 primary adenocarcinomas of the stomach and one lymph node metastasis of a gastric adenocarcinoma after direct harvesting or short-term in vitro culture. All cases showed a variable number of numerical and/or structural clonal cytogenetic aberrations. Polysomy of chromosomes 2 and 20 were the most common numerical abnormalities. Rearrangements of chromosomes 1, 3, 7, and 13 were each observed in more than half the cases. Chromosomes 3 and 13 were the chromosomes more often exhibiting structural cytogenetic aberrations. In five tumors, rearrangements of chromosome 6 resulting in partial deletion of 6q were noted (common deleted region 6q21-22-->qter). The recurrent markers observed in our series were an i(8q) and an i(17q) in three and two cases, respectively. Double minutes (dmin) or homogeneously staining regions (hsr) were evident in three tumors. Contrary to the recent claim that structural abnormalities affecting 11p13-p15 were specifically involved in gastric cancer, we detected rearrangements of this region in only two cases.

Cytogenetic findings in 18 follicular thyroid adenomas

Cytogenetic study of 18 follicular thyroid adenomas showed clonal chromosome changes in 12 tumors. These results suggest the existence of at least three cytogenetically distinct subgroups: a hyperploid group characterized by the presence of a cluster of numerical changes including +5, +7, and +12 as the most frequent anomalies and, less frequently, +4, +9, +14, +16, and +17; a pseudo- or near-diploid group characterized by simple karyotypic aberrations; and a cytogenetically normal group.

P53 mutations in gastric carcinomas.

We carried out an immunohistochemical study and DNA analysis of 30 gastric carcinomas to evaluate p53 overexpression and allelic loss at 17p. The immunohistochemical study demonstrated immunoreactivity for p53 protein in four cases. Allelic loss for the pYNZ22.1 marker was detected in nine cases. In total, ten cases showed immunoreactivity for p53 protein, allelic loss, or both. The study of nine of these cases by constant denaturant gel electrophoresis revealed p53 mutations in three cases. We conclude that the prevalence of mutations of p53 in our series is similar to what has recently been observed in other cases of gastric cancer, but lower than in colon carcinomas.

Increasing Levels of MYC and MET Co-Amplification During Tumor Progression of a Case of Gastric Cancer

The cytogenetic study of a nodal metastasis from a gastric carcinoma, after two passages in nude mice, revealed a large number of double minutes. Comparative genomic in situ hybridization (CGH) analysis using DNA extracted from this xenograft revealed the existence of three clear amplification units that originated from the chromosomal subregions 6q24-25, 7q31-32, and 8q24 in the xenograft DNA. Similar, though less prominent, CGH results were found with DNAs extracted from the primary tumor and its metastasis, implying that the same amplicons were also present, albeit less abundantly, in the DNAs of these neoplastic tissues. Southern analysis of the second-passage xenograft detected 18- and 10-fold amplification of MET (located at 7q31) and MYC (located at 8q24), respectively. The retrospective study of the first passage of the xenograft, as well as of the metastatic and primary tumors before xenografting, showed amplification levels of MET of, respectively, 12-, 9-, and 5-fold and MYC of, respectively, 8-, 7-, and 5-fold. Our results suggest that increased levels of co-amplification of MYC and MET correlate with enhanced growth potential in this case of gastric carcinoma.

MSI phenotype and MMR alterations in familial and sporadic gastric cancer.

Microsatellite instability (MSI) is a major pathway involved in gastric carcinogenesis occurring in 20% of gastric cancer (GC). However, it is not clear whether MSI phenotype preferentially occurs in the sporadic or familial GC, when stringent inclusion criteria are used. The aim of this study was to compare the frequency of MSI and hypermethylation of MLH1 promoter in a large series of familial GC patients (non‐HNPCC and non‐CDH1‐related) and sporadic cases. Additionally, we analysed the immunoexpression of MMR proteins in a fraction of cases. Overall, the frequency of familial GC was 7.1%, and the frequency of hereditary tumours was 4.6%. MSI phenotype and MLH1 hypermethylation frequencies were not statistical different between familial and sporadic GC settings. Further, the MSI phenotype was not associated with any clinico‐pathological features studied in the familial GC setting, whereas in the sporadic setting, it was associated with older age, female gender and intestinal histotype. Using our stringent Amsterdam‐based clinical criteria to select familial GC (number of cases, age of onset), we verified that sporadic and familial cases differed in gender but shared histopathological features. We verified that the frequency of MSI was similar in familial and sporadic GC settings, demonstrating that this molecular phenotype is not a hallmark of familial GC in contrast to what is verified in HNPCC. Moreover, we observed that the frequency of MLH1 hypermethylation is similar in sporadic and familial cases suggesting that in both settings MSI is not associated to MMR genetic alterations but in contrast to epigenetic deregulation.

Follicular thyroid carcinoma: Chromosome analysis of 19 cases

Short‐term cultures of 19 follicular thyroid carcinomas were examined cytogenetically. Clonal chromosomal changes were detected in 12 tumors. Two follicular carcinomas had only numerical alterations: one with a hyperdiploid karyotype with trisomies/polysomies of chromosomes 7 and 12, similar to the karyotypes previously identified in a sub‐group of benign thyroid lesions, and the other with monosomy 20. In the remaining ten cases several structural chromosome anomalies were found. Loss of the short arm of chromosome 3 was observed in one tumor. In two widely invasive and metastasizing follicular carcinomas there was a t(7;8)(p15;q24) as the sole abnormality in one case and a der(8)t(7;8)(p15;q24) together with other cytogenetic alterations in the other case. This finding suggests that t(7;8)(p15;q24) may be related to an aggressive behavior of follicular thyroid carcinomas. Genes Chromosomes Cancer 21:250–255, 1998.

Highly sensitive detection of the MGB1 transcript (mammaglobin) in the peripheral blood of breast cancer patients.

We describe a new one‐step RT‐PCR assay for the detection of the mammaglobin (MGB1) gene transcript in the peripheral blood of breast cancer patients. With this approach, the MGB1 transcript could be detected in the peripheral blood of 22 of 54 (41%) breast cancer patients prior to any therapy. This method, using specific primers for cDNA synthesis, proved to be more sensitive (10−6 to 10−11, usually 10−7) than previously reported methodologies. This increased sensitivity was achieved without compromising specificity, as the MGB1 transcript was not detected in 38 blood samples of healthy donors and in only 1 of 18 blood samples of patients presenting with hematologic malignancies. A positive correlation was seen between MGB1 positivity and breast cancer stage: 0/3 (0%) in stage 0, 3/13 (23%) in stage I, 6/17 (35%) in stage II, 5/10 (50%) in stage III, 8/11 (73%) in stage IV (p = 0.003). The prognostic and therapeutic implications of MGB1 positivity by one‐step RT‐PCR in the peripheral blood of breast cancer patients, especially in clinically localized disease (stages I and II), should be evaluated after long‐term clinical follow‐up of these patients.