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Transarterial chemoembolization (TACE) is used to treat patients with unresectable hepatocellular carcinoma (HCC). We evaluated the clinical impact of a-fetoprotein (AFP) and circulating cell-free and tumor DNA (cfDNA and ctDNA) changes around the TACE procedure. Our prospective monocentric study enrolled consecutive patients treated with TACE, with samples collected at baseline (D - 1), Day 2 (D + 2) and 1 month (M + 1) after TACE. cfDNA was quantified by the fluorometric method, and ctDNA was quantified by digital polymerase chain reaction designed for two hotspot TERT mutations. Computerized tomography scans or magnetic resonance imaging were performed at M + 1 every 3 months following TACE and independently reviewed. The objective was to identify thresholds of cfDNA, ctDNA and AFP changes associated with progressive disease (PD) using receiver operating characteristic curves. Thirty-eight patients were included from March 2018 to March 2019. All markers significantly increased from D - 1 to D + 2 (P < .005), and cfDNA and ctDNA significantly decreased from D + 2 to M + 1 (P < .0001). The analysis of changes from D - 1 to M + 1 identified thresholds at +31.4% for cfDNA and 0% for ctDNA that were significantly associated with PD at M + 1 (44.4% [>+31.4%] vs 3.8% [≤+31.4%] and 50.0% [>0%] vs 5.0% [≤0%], respectively). No significant threshold was identified for AFP. Using a score combining cfDNA and ctDNA, the patients were classified into high- or low-risk PD groups at M + 1, with PD rates of 80.0% vs 4.3% (P = .001) and median progression-free survival times of 1.3 vs 10.3 months (P = .002). Our study suggests that cfDNA and ctDNA increases around the TACE procedure and are associated with therapeutic failure., (© 2021 UICC.)

Single-nucleotide polymorphisms (SNPs) in over 180 loci have been associated with breast cancer (BC) through genome-wide association studies involving mostly unselected population-based case-control series. Some of them modify BC risk of women carrying a BRCA1 or BRCA2 (BRCA1/2) mutation and may also explain BC risk variability in BC-prone families with no BRCA1/2 mutation. Here, we assessed the contribution of SNPs of the iCOGS array in GENESIS consisting of BC cases with no BRCA1/2 mutation and a sister with BC, and population controls. Genotyping data were available for 1281 index cases, 731 sisters with BC, 457 unaffected sisters and 1272 controls. In addition to the standard SNP-level analysis using index cases and controls, we performed pedigree-based association tests to capture transmission information in the sibships. We also performed gene- and pathway-level analyses to maximize the power to detect associations with lower-frequency SNPs or those with modest effect sizes. While SNP-level analyses identified 18 loci, gene-level analyses identified 112 genes. Furthermore, 31 Kyoto Encyclopedia of Genes and Genomes and 7 Atlas of Cancer Signaling Network pathways were highlighted (false discovery rate of 5%). Using results from the "index case-control" analysis, we built pathway-derived polygenic risk scores (PRS) and assessed their performance in the population-based CECILE study and in a data set composed of GENESIS-affected sisters and CECILE controls. Although these PRS had poor predictive value in the general population, they performed better than a PRS built using our SNP-level findings, and we found that the joint effect of family history and PRS needs to be considered in risk prediction models., (© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Discriminating which nucleotide variants cause disease or contribute to phenotypic traits remains a major challenge in human genetics. In theory, any intragenic variant can potentially affect RNA splicing by altering splicing regulatory elements (SREs). However, these alterations are often ignored mainly because pioneer SRE predictors have proved inefficient. Here, we report the first large-scale comparative evaluation of four user-friendly SRE-dedicated algorithms (QUEPASA, HEXplorer, SPANR, and HAL) tested both as standalone tools and in multiple combined ways based on two independent benchmark datasets adding up to >1,300 exonic variants studied at the messenger RNA level and mapping to 89 different disease-causing genes. These methods display good predictive power, based on decision thresholds derived from the receiver operating characteristics curve analyses, with QUEPASA and HAL having the best accuracies either as standalone or in combination. Still, overall there was a tight race between the four predictors, suggesting that all methods may be of use. Additionally, QUEPASA and HEXplorer may be beneficial as well for predicting variant-induced creation of pseudoexons deep within introns. Our study highlights the potential of SRE predictors as filtering tools for identifying disease-causing candidates among the plethora of variants detected by high-throughput DNA sequencing and provides guidance for their use in genomic medicine settings., (© 2020 Wiley Periodicals LLC.)

Objective: Primary familial brain calcification (PFBC) is a rare cerebral microvascular calcifying disorder with diverse neuropsychiatric expression. Five genes were reported as PFBC causative when carrying pathogenic variants. Haploinsufficiency of SLC20A2, which encodes an inorganic phosphate importer, is a major cause of autosomal-dominant PFBC. However, PFBC remains genetically unexplained in a proportion of patients, suggesting the existence of additional genes or cryptic mutations. We analyzed exome sequencing data of 71 unrelated, genetically unexplained PFBC patients with the aim to detect copy number variations that may disrupt the expression of core PFBC-causing genes., Methods: After the identification of a deletion upstream of SLC20A2, we assessed its consequences on gene function by reverse transcriptase droplet digital polymerase chain reaction (RT-ddPCR), an ex vivo inorganic phosphate uptake assay, and introduced the deletion of a putative SLC20A2 enhancer mapping to this region in human embryonic kidney 293 (HEK293) cells by clustered regularly interspaced short palindromic repeats (CRISPR) - CRISPR-associated protein 9 (Cas9)., Results: The 8p11.21 deletion, segregating with PFBC in a family, mapped 35 kb upstream of SLC20A2. The deletion carriers/normal controls ratio of relative SLC20A2 mRNA levels was 60.2% (P < 0.001). This was comparable with that of patients carrying an SLC20A2 premature stop codon (63.4%; P < 0.001). The proband exhibited a 39.3% decrease of inorganic phosphate uptake in blood (P = 0.015). In HEK293 cells, we observed a 39.8% decrease in relative SLC20A2 mRNA levels after normalization on DNA copy number (P < 0.001)., Discussion: We identified a deletion of an enhancer of SLC20A2 expression, with carriers showing haploinsufficiency in similar ranges to loss-of-function alleles, and we observed reduced mRNA levels after deleting this element in a cellular model. We propose a 3-step strategy to identify and easily assess the effect of such events. © 2020 International Parkinson and Movement Disorder Society., (© 2020 International Parkinson and Movement Disorder Society.)

Sirenomelia is a rare severe malformation sequence of unknown cause characterized by fused legs and severe visceral abnormalities. We present a series of nine families including two rare familial aggregations of sirenomelia investigated by a trio-based exome sequencing strategy. This approach identified CDX2 variants in the two familial aggregations, both fitting an autosomal dominant pattern of inheritance with variable expressivity. CDX2 is a major regulator of caudal development in vertebrate and mouse heterozygotes are a previously described model of sirenomelia. Remarkably, the p.(Arg237His) variant has already been reported in a patient with persistent cloaca. Analysis of the sporadic cases revealed six additional candidate variants including a de novo frameshift variant in the genetically constrained NKD1 gene, encoding a known interactor of CDX2. We provide the first insights for a genetic contribution in human sirenomelia and highlight the role of Cdx and Wnt signaling pathways in the development of this disorder., (© 2020 Wiley Periodicals, Inc.)

Burkitt lymphoma (BL) is characterized by a translocation of the MYC oncogene that leads to the upregulation of MYC expression, cell growth and proliferation. It is well-established that MYC translocation is not a sufficient genetic event to cause BL. Next-generation sequencing has recently provided a comprehensive analysis of the landscape of additional genetic events that contribute to BL lymphomagenesis. Refractory BL or relapsing BL are almost always incurable as a result of the selection of a highly chemoresistant clonally related cell population. Conversely, a few BL recurrence cases arising from clonally distinct tumors have been reported and were associated with a favorable outcome similar to that reported for first-line treatment. Here, we used an unusual case of recurrent but clonally distinct EBV+ BL to highlight the key genetic events that drive BL lymphomagenesis. By whole exome sequencing, we established that ID3 gene was targeted by distinct mutations in the two clonally unrelated diseases, highlighting the crucial role of this gene during lymphomagenesis. We also detected a heterozygous E1021K PIK3CD mutation, thus increasing the spectrum of somatic mutations altering the PI3K signaling pathway in BL. Interestingly, this mutation is known to be associated with activated phosphoinositide 3-kinase delta syndrome (APDS). Finally, we also identified an inherited heterozygous truncating c.5791CT FANCM mutation that may contribute to the unusual recurrence of BL., (© 2019 The Authors. Genes, Chromosomes & Cancer published by Wiley Periodicals, Inc.)

Pathogenic variants in BRCA1 and BRCA2 only explain the underlying genetic cause of about 10% of hereditary breast and ovarian cancer families. Because of cost-effectiveness, multigene panel testing is often performed even if the clinical utility of testing most of the genes remains questionable. The purpose of our study was to assess the contribution of rare, deleterious-predicted variants in DNA repair genes in familial breast cancer (BC) in a well-characterized and homogeneous population. We analyzed 113 DNA repair genes selected from either an exome sequencing or a candidate gene approach in the GENESIS study, which includes familial BC cases with no BRCA1 or BRCA2 mutation and having a sister with BC (N = 1,207), and general population controls (N = 1,199). Sequencing data were filtered for rare loss-of-function variants (LoF) and likely deleterious missense variants (MV). We confirmed associations between LoF and MV in PALB2, ATM and CHEK2 and BC occurrence. We also identified for the first time associations between FANCI, MAST1, POLH and RTEL1 and BC susceptibility. Unlike other associated genes, carriers of an ATM LoF had a significantly higher risk of developing BC than carriers of an ATM MV (OR LoF = 17.4 vs. OR MV = 1.6; p Het = 0.002). Hence, our approach allowed us to specify BC relative risks associated with deleterious-predicted variants in PALB2, ATM and CHEK2 and to add MAST1, POLH, RTEL1 and FANCI to the list of DNA repair genes possibly involved in BC susceptibility. We also highlight that different types of variants within the same gene can lead to different risk estimates., (© 2018 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Acquired estrogen receptor gene (ESR1) mutations have been recently reported as a marker of resistance to aromatase inhibitors in hormone receptor positive metastatic breast cancer. We retrospectively considered seven patients treated for metastatic breast cancer with available samples from the primary tumor before any treatment, cryopreserved metastasis removed during progression and concomitant plasmas. All these seven patients were in disease progression after previous exposure to aromatase inhibitors for at least 6 months, and were assessed for ESR1 mutations detection in tumor and circulating DNA. For these patients, Sanger sequencing identified four metastases with clear ESR1 mutation and one possible, whereas digital PCR identified six mutated metastases. Then, under blind conditions and using digital PCR, corresponding circulating ESR1 mutations were successfully detected in four of these six metastatic breast cancer patients. Moreover, in two patients with serial blood samples following treatments exposure, the monitoring of circulating ESR1 mutations clearly predicted disease evolution. In the context of high interest for ESR1 mutations, our results highlight that these acquired recurrent mutations may be tracked in circulating tumor DNA and may be of clinical relevance for metastatic breast cancer patient monitoring., (© 2015 UICC.)

Next-generation sequencing (NGS) has allowed a tremendous progress in the characterization of the molecular bases of genetic diseases and the last annual American Society of Human Genetics meeting has highlighted the implementation of whole exome sequencing in medical genetics. Several investigators suggest that it should be medically relevant for each individual to have the exome sequenced. These perspectives do not take into account the complexity of genetic variation interpretation and genetic determinism of human diseases: an important limiting step of targeted analyses of gene(s) involved in Mendelian diseases is already the interpretation of variants of unknown significance; most of the 20,000 single nucleotide variations present in each exome, even those having a very low allelic frequency, are not deleterious; the genetic determinism of the majority of human diseases involves either a combination of numerous genetic variations, each conferring a slightly increased risk, or rare genetic variations with a strong effect, but the demonstration of their involvement in diseases is particularly challenging. The challenge for the next generation of medical geneticists will be to integrate the technological power of NGS technologies, the complexity of genome interpretation, the importance of phenotyping before genotyping, and the guidelines of medical genetics raised in the pre-NGS era., (© 2014 WILEY PERIODICALS, INC.)

To identify novel genetic bases of early-onset epithelial ovarian tumors, we used the trio exome sequencing strategy in a patient without familial history of cancer who presented metastatic serous ovarian adenocarcinomas at 21 years of age. We identified a single de novo mutation (c.1157A>G/p.Asn386Ser) within the INHBA gene encoding the βA-subunit of inhibins/activins, which play a key role in ovarian development. In vitro, this mutation alters the ratio of secreted activins and inhibins. In a second patient with early-onset serous borderline papillary cystadenoma, we identified an unreported germline mutation (c.179G>T/p.Arg60Leu) of the INHA gene encoding the α-subunit, the partner of the βA-subunit. This mutation also alters the secreted activin/inhibin ratio, by disrupting both inhibin A and inhibin B biosynthesis. In a cohort of 62 cases, we detected an additional unreported germline mutation of the INHBA gene (c.839G>A/p.Gly280Glu). Our results strongly suggest that inhibin mutations contribute to the genetic determinism of epithelial ovarian tumors., (© 2013 The Authors. *Human Mutation published by Wiley Periodicals, Inc.)

In contrast to other tumor suppressor genes, the majority of TP53 alterations are missense mutations. We have previously reported that in the Li-Fraumeni syndrome (LFS), germline TP53 missense mutations are associated with an earlier age of tumor onset. In a larger series, we observed that mean age of tumor onset in patients harboring dominant negative missense mutations and clearly null mutations was 22.6 and 37.5 years, respectively. To assess the impact of heterozygous germline TP53 mutations in the genetic context of the patients, we developed a new functional assay of the p53 pathway on the basis of induction of DNA damage in Epstein-Barr-virus-immortalized lymphocytes, followed by comparative gene-expression profiling. In wild-type lymphocytes, we identified a core of 173 genes whose expression was induced more than twofold, of which 46 were known p53 target genes. In LFS lymphocytes with canonical missense mutations, the number of induced genes and the level of known p53 target genes induction were strongly reduced as compared with controls and LFS lymphocytes with null mutations. These results show that certain germline missense TP53 mutations, such as those with dominant negative effect, dramatically alter the response to DNA damage. This probably explains why TP53 alterations are predominantly missense mutations., (© 2012 Wiley Periodicals, Inc.)

Classification of rare missense substitutions observed during genetic testing for patient management is a considerable problem in clinical genetics. The Bayesian integrated evaluation of unclassified variants is a solution originally developed for BRCA1/2. Here, we take a step toward an analogous system for the mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) that confer colon cancer susceptibility in Lynch syndrome by calibrating in silico tools to estimate prior probabilities of pathogenicity for MMR gene missense substitutions. A qualitative five-class classification system was developed and applied to 143 MMR missense variants. This identified 74 missense substitutions suitable for calibration. These substitutions were scored using six different in silico tools (Align-Grantham Variation Grantham Deviation, multivariate analysis of protein polymorphisms [MAPP], MutPred, PolyPhen-2.1, Sorting Intolerant From Tolerant, and Xvar), using curated MMR multiple sequence alignments where possible. The output from each tool was calibrated by regression against the classifications of the 74 missense substitutions; these calibrated outputs are interpretable as prior probabilities of pathogenicity. MAPP was the most accurate tool and MAPP + PolyPhen-2.1 provided the best-combined model (R(2)  = 0.62 and area under receiver operating characteristic = 0.93). The MAPP + PolyPhen-2.1 output is sufficiently predictive to feed as a continuous variable into the quantitative Bayesian integrated evaluation for clinical classification of MMR gene missense substitutions., (© 2012 Wiley Periodicals, Inc.)

Fumarase deficiency (FD), caused by biallelic alteration of the Fumarase Hydratase gene (FH), and a rare metabolic disorder that affects the Krebs cycle, causes severe neurological impairment and fumaric aciduria. Less than 30 unrelated cases are known to date. In addition, heterozygous mutations of the FH gene are responsible for hereditary leiomyomatosis and renal cell cancer (HLRCC). We report three additional patients with dramatically different clinical presentations of FD and novel missense mutations in the FH gene. One patient had severe neonatal encephalopathy, polymicrogyria, <1% enzyme activity, and mildly increased levels of urinary fumarate. The second patient had microcephaly, mental retardation, 20% of fumarase activity, and intermediate levels of urinary fumarate. The third patient had mild mental retardation, polymicrogyria, 42-61% enzyme activity in different cell types and massive amounts of urinary fumarate. In silico analysis predicted minor yet significant structural changes in the encoded proteins. The nuclear translocation of hypoxia-inducible factor (HIF)-1alpha (HIF1A) in cultured fibroblasts was similar to controls. These results extend the range of clinical and biochemical variation associated with FD, supporting the notion that patients with moderate increases in fumarate excretion should be investigated for this disease. The tumoral risk in the patients and their relatives requires adequate screening protocols., (© 2011 Wiley-Liss, Inc.)

Type I hyperprolinemia (HPI) is an autosomal recessive disorder associated with cognitive and psychiatric troubles, caused by alterations of the Proline Dehydrogenase gene (PRODH) at 22q11. HPI results from PRODH deletion and/or missense mutations reducing proline oxidase (POX) activity. The goals of this study were first to measure in controls the frequency of PRODH variations described in HPI patients, second to assess the functional effect of PRODH mutations on POX activity, and finally to establish genotype/enzymatic activity correlations in a new series of HPI patients. Eight of 14 variants occurred at polymorphic frequency in 114 controls. POX activity was determined for six novel mutations and two haplotypes. The c.1331G>A, p.G444D allele has a drastic effect, whereas the c.23C>T, p.P8L allele and the c.[56C>A; 172G>A], p.[Q19P; A58T] haplotype result in a moderate decrease in activity. Among the 19 HPI patients, 10 had a predicted residual activity <50%. Eight out of nine subjects with a predicted residual activity > or = 50% bore at least one c.824C>A, p.T275N allele, which has no detrimental effect on activity but whose frequency in controls is only 3%. Our results suggest that PRODH mutations lead to a decreased POX activity or affect other biological parameters causing hyperprolinemia.

A heterozygous genomic deletion removing exons 6 to 9 of the microtubule associated protein tau (MAPT) gene, predicting to result into a truncated protein lacking the first microtubule binding domain, was detected in a patient with frontotemporal dementia (FTD). Cell culture experiments showed that the truncated tau isoforms had a dramatic decrease in the normal binding to microtubules but acquired the ability to bind microtubule associated protein-1B (MAP-1B). This indicates that this tauopathy likely results both from a loss of function mechanism and from a deleterious gain of function by which cytoplasmic deleted forms of tau sequester another MAP. Both mechanisms could contribute to impair microtubule dynamics., ((c) 2009 Wiley-Liss, Inc.)

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal disorder caused by mutations in DNA mismatch repair (MMR) genes. Tumors of the HNPCC-spectrum are associated with microsatellite instability (MSI) and loss of MMR protein expression. Lymphomas are not considered to be HNPCC-related tumors. We report and analyze a case of an HNPCC patient with three colorectal cancers and a B-cell non-Hodgkin lymphoma. Quantitative multiplex PCR of short fluorescent fragments detected a novel MSH2 rearrangement involving exons 9 and 10, which proved to be the pathogenic cause of the disease in the family. Tumor tissues including the lymphoma showed MSI and loss of MSH2 expression. Multiplex ligation-dependent probe amplification analysis revealed a somatic loss of the wild-type MSH2 allele in the lymphoma. These results support the fact that the total loss of a MMR gene can lead to lymphomagenesis, as seen in biallelic MMR-deficient families and knockout mice. Moreover, this is the first report of a B-cell non-Hodgkin lymphoma with a loss of the MSH2 protein expression, linked to a heterozygous germline MSH2 mutation in an HNPCC family., ((c) 2008 Wiley-Liss, Inc.)

We describe the biological consequences on PSEN1 exons 8 or 9 splicing and Abeta peptides production of four PSEN1 mutations associated with a phenotypic variant of Alzheimer disease, which includes cotton wool plaques and spastic paraparesis (CWP/SP). Two of these mutations (c.869-22&#95;869-23ins18 and c.871A > C, p.T291P) are novel mutations located in intron 8 and exon 9, respectively. The c.869-22&#95;869-23ins18 mutation caused exon 9 skipping whereas the c.871A > C (p.T291P) mutation showed only a modest effect on exon 9 skipping. The previously reported E280G and P264L mutations, located in exon 8, had no effect on mRNA splicing. Infection of cells with mutant T291P, E280G, or P264L cDNAs caused a variable increase in secreted Abeta42. We conclude that none of the previously proposed mechanisms, i.e. exceptionally large increases in secreted Abeta42 levels or loss of PSEN1 exons 8 or 9, provides complete explanation of the CWP/SP phenotype.

MSH2 rearrangements are involved in approximately 10% of hereditary non-polyposis colorectal cancer (HNPCC) families, and in most of the rearrangements, exon 1 is deleted. We scanned by quantitative multiplex polymerase chain reaction (PCR) of short fluorescent fragments (QMPSF) 200 kb of genomic sequences upstream of the MSH2 transcription initiation site in 21 HNPCC families with exon 1 deletions. This QMPSF scan revealed 12 distinct 5' breakpoints located up to 200 kb upstream of the MSH2 transcription initiation site. Sequencing analysis of the rearranged allele in 17 families revealed that most of the deletions (15/17) resulted from homologous Alu-mediated recombination. QMPSF and sequencing analysis in these 21 families led us to detect the presence of 20 distinct 5' breakpoints. In 14 out of 15 Alu-mediated recombinations, we found, either within the identical region in which the recombination had probably occurred or in its vicinity, the 26-bp Alu core sequence containing the recombinogenic Chi-like motif. Compared to the equivalent regions of other human genes, the MSH2 upstream region was found to contain a high density of Alu repeats (30% within 228 kb and 43% within 50 kb), most of which belong to the old Alu S subfamilies. In conclusion, this study demonstrates the heterogeneity of the breakpoints within the MSH2 upstream region and reveals the remarkable density of recombinogenic Alu sequences in this region.

Recently, a single nucleotide polymorphism that results in an amino acid change (Q7R) was identified in a previously undescribed gene, named saitohin, nested within the tau gene. We analyzed the distribution of this polymorphism in 499 patients with Alzheimer's disease, 91 patients with frontotemporal dementia, and 402 controls. This polymorphism was in complete disequilibrium with the well-defined extended tau haplotype. We failed to replicate the association between the RR genotype and late-onset Alzheimer's disease, but we found a trend toward an association between the QQ genotype and frontotemporal dementia. Thus, the saitohin Q allele, which is a novel determinant of the tau H1 haplotypes, might represent a causative factor involved in the determinism of several tauopathies.

Recent studies have revealed a significant proportion of BRCA1 exon deletions or duplications in breast-ovarian cancer families with high probability of BRCA1- or BRCA2-linked predisposition, in which mutations of these genes have not been found. The difficulty of detecting such heterozygous rearrangements has stimulated the development of several new screening methods. Quantitative fluorescent multiplex PCR is based on simultaneous amplification of multiple target sequences under conditions that allow rapid and reliable quantitative comparison of the fluorescence of each amplicon in test samples and in controls. The modified method described here, named quantitative multiplex PCR of short fluorescent fragments (QMPSF), is particularly well suited for large genes. All BRCA1 coding exons were analyzed using four multiplexes in 52 families without point mutations in the exons or splice-sites of BRCA1 and BRCA2, and selected because of high probability of a BRCA1- or BRCA2-linked genetic predisposition. Five distinct BRCA1 rearrangements were detected: a deletion of exons 8-13, a duplication of exons 3-8, a duplication of exons 18-20, a deletion of exons 15-16, and a deletion of exons 1-22-which is the largest deletion found so far within the BRCA1 gene. The method described here lends itself to rapid, sensitive, and cost-effective search of BRCA1 rearrangements and may be included into the routine molecular analysis of breast-ovarian cancer predispositions. Hum Mutat 20:218-226, 2002., (Copyright 2002 Wiley-Liss, Inc.)

Multiple primary cancers are one of the hallmarks of inherited predisposition. Outside the familial context, multiple primary tumors could be related either to germline de novo mutations or to low-penetrance mutations, in predisposing genes. We selected 100 patients who displayed multiple primary melanoma (MPM) without any known melanoma cases recorded within their families and looked for germline mutations in the two melanoma-predisposing genes identified to date, CDKN2A and CDK4 exon 2. Nine patients (9%) had germline mutations in CDKN2A, whereas none carried germline mutations in exon 2 of CDK4. Seven cases displayed a recurrent missense mutation, G101W, already described in more than 20 melanoma-prone families; one case carried a missense mutation never reported to date (P114S), and the last case was a carrier of a 6 bp insertion at nucleotide 57 resulting in a duplication of codons 18 and 19. To ascertain whether the G101W was a mutational hot spot for de novo mutations or a common founder mutation, we genotyped eight microsatellite markers flanking the CDKN2A gene. After allowing for recombination over time, haplotype sharing provided evidence for an original G101W mutation common to 6 out of 7 sporadic MPM cases. Therefore, it can be concluded that de novo germline CDKN2A mutations associated with MPM are rare., (Copyright 2001 Wiley-Liss, Inc.)

A woman with a family history of brain tumors in her daughter and sister presented with a breast cancer. She subsequently developed two metachronous primary tumors: a small-cell lung cancer and a colon carcinoma. These tumors arose within the internal mammary radiotherapy field and within the field irradiated for ovariolysis. The p53 gene was analyzed in whole blood lymphocytes using a functional assay developed in yeast Saccharomyces cerevisiae, which tests the transcriptional competence of p53. DNA from the colon cancer cells was analyzed by polymerase chain reaction and sequencing. The patient had a germline-inactivating p53 mutation, confirming the diagnosis of Li-Fraumeni syndrome (LFS). The colon tumor and the lung tumor both conserved the mutant p53 allele but had lost the wild-type allele. This observation and the experimental data suggest an abnormal sensitivity of LFS patients to radiogenic carcinogenesis. The indications and extent of radiotherapy in patients with a clinical or molecular diagnosis of LFS should be discussed individually and should take into account the risk of secondary neoplasms arising in the radiation fields., (Copyright 2001 Wiley-Liss, Inc.)