Mario Falchetti

Genome-wide expression profile of sporadic gastric cancers with microsatellite instability

Gastric cancers with mismatch repair (MMR) inactivation are characterised by microsatellite instability (MSI). In this study, the transcriptional profile of 38 gastric cancers with and without MSI was analysed. Unsupervised analysis showed that the immune and apoptotic gene networks efficiently discriminated these two cancer types. Hierarchical clustering analysis revealed numerous gene expression changes associated with the MSI phenotype. Amongst these, the p53-responsive genes maspin and 14-3-3 sigma were significantly more expressed in tumours with than without MSI. A tight immunosurveillance coupled with a functional p53 gene response is consistent with the better prognosis of MSI cancers. Frequent silencing of MLH1 and downregulation of MMR target genes, such as MRE11 and MBD4, characterised MSI tumours. The downregulation of SMUG1 was also a typical feature of these tumours. The DNA repair gene expression profile of gastric cancer with MSI is of relevance for therapy response.

Gastric cancer with high-level microsatellite instability: target gene mutations, clinicopathologic features, and long-term survival

Gastric cancer is one of the leading causes of cancer death worldwide, and although the incidence has decreased in Western countries, specific high-risk areas are present in Italy. Gastric cancer with high-level microsatellite instability (MSI-H) represents a well-defined subset of carcinomas showing distinctive clinicopathologic features. We examined clinicopathologic associations and long-term survival in a series of 159 gastric cancer cases from a high-risk population in Tuscany (central Italy). MSI-H was associated with antral location of the tumor (P = .001), intestinal type according to Lauren classification (P = .002), expanding type according to Ming classification (P = .0001), and mucinous histologic type according to the Japanese Research Society for Gastric Cancer classification (P = .002). In addition, MSI-H was strongly associated with a higher survival at 15 years (P = .01) and with loss of hMLH1 expression, evaluated by immunohistochemistry (P = .001). Multivariate analyses showed a significant association between the absence of hMLH1 reactivity and the expanding tumor type (P = .002). We also investigated the MSI-H-related genetic changes by analyzing coding repeats within target genes involved in pathways that control cell growth (TGFbetaRII, IGFIIR, RIZ, TCF4, DP2), apoptosis (BAX, BCL10, FAS, CASPASE5, APAF1), and DNA repair genes (hMSH6, hMSH3, MED1, RAD50, BLM, ATR, BRCA2, MRE11). Gastric cancer cases with MSI-H were found to accumulate heterozygous mutations affecting multiple molecular pathways and multiple genes within each pathway. Intriguingly, in this subset, TGFbetaRII mutations appeared to be inversely related to BLM mutations (P = .006), whereas RAD50 mutation carriers showed significantly reduced survival (P = .03).

Mutations at coding mononucleotide repeats in gastric cancer with the microsatellite mutator phenotype

We analysed 50 gastric carcinomas (GCs) to verify whether mutations at coding repeats were associated with microsatellite instability (MSI). The tumors included: ten cases with no MSI, 14 cases with MSI=1 locus, 13 cases with MSI=two loci and 13 cases with MSI⩾3 loci. We investigated coding repeats within the TGF-β RII, IGFIIR, BAX, hMSH6, hMSH3 and BRCA2 genes. The TGF-β RII, IGFIIR, BAX, hMSH6 and hMSH3 repeats were altered in 11 (22%), five (10%), four (8%), 16 (32%) and five (10%) cases respectively. Mutations occurred only in MSI-positive (MSI+) tumors and correlated with increasing MSI levels. No alterations of the BRCA2 repeat were found. Mutations in genes other than hMSH6 were strongly associated to hMSH6 mutations, suggesting a key role of this gene. The non-coding BAT-26 and E-Cadherin 3′ UTR poly(A)8/(T)15 repeats were analysed in 44 of the 50 cases. Novel tumor-associated alleles were observed only in MSI-positive GCs and were in most cases associated with mutations at coding repeats. Further investigations with BAT-40 confirmed that four cases manifested mononucleotide repeat alterations restricted to hMSH6 and one case to TGF-β RII. A subset of tumors with MSI at two or more dinucleotide loci resulted negative for mutations at coding and non-coding mononucleotide repeats.

BRCA1/BRCA2 rearrangements and CHEK2 common mutations are infrequent in Italian male breast cancer cases

Male breast cancer (MBC) is a rare and poorly known disease. Germ-line mutations of BRCA2 and, to lesser extent, BRCA1 genes are the highest risk factors associated with MBC. Interestingly, BRCA2 germ-line rearrangements have been described in high-risk breast/ovarian cancer families which included at least one MBC case. Germ-line mutations of CHEK2 gene have been also implicated in inherited MBC predisposition. The CHEK2 1100delC mutation has been shown to increase the risk of breast cancer in men lacking BRCA1/BRCA2 mutations. Intriguingly, two other CHEK2 mutations (IVS2+1G>A and I157T) and a CHEK2 large genomic deletion (del9-10) have been associated with an elevated risk for prostate cancer. Here, we investigated the contribution of BRCA1, BRCA2 and CHEK2 alterations to MBC predisposition in Italy by analysing a large series of MBC cases, unselected for breast cancer family history and all negative for BRCA1/BRCA2 germ-line mutations. A total of 102 unrelated Italian MBC cases were screened for deletions/duplications of BRCA1, BRCA2 and CHEK2 by multiplex ligation-dependent probe amplification. No BRCA1, BRCA2 and CHEK2 genomic rearrangements, including the CHEK2 del9-10, were found in the series analysed. Furthermore, none of the MBC cases and 263 male population controls, also included in this study, carried the CHEK2 1100delC, IVS2+1G>A and I157T common mutations. Overall, our data suggest that screening of BRCA1/2 rearrangements is not advantageous in MBC cases not belonging to high-risk breast cancer families and that common CHEK2 mutations play an irrelevant role in MBC predisposition in Italy.

ErbB-receptors expression and survival in breast carcinoma: A 15-year follow-up study

Aberrant expression of the epidermal growth factor receptor family has been implicated in the pathogenesis and progression of breast cancer and associated with poor prognosis. To evaluate the prognostic impact of the ErbB receptors expression profile, we analyzed a well‐characterized series of 145 primary breast carcinomas for the simultaneous expression of epidermal growth factor receptor (EGFR/HER‐1), ErbB‐2 (HER‐2), ErbB‐3 (HER‐3), and ErbB‐4 (HER‐4), using immunohistochemistry. Tumors were considered negative or positive for each marker when less than or more than 25% of the cancer cells were immunopositive. Expression of EGFR, ErbB‐2, ErbB‐3, and ErbB‐4 was observed in 31 (21.4%), 65 (44.8%), 72 (49.7%), and 81 (55.9%) of the cases, respectively. There were significant associations between EGFR expression and pT status (P = 0.01), and between ErbB‐3 expression and pN (P = 0.003), menopausal (P = 0.01) and PR (P < 0.001) status. The majority of the cases co‐expressed two or more receptors. ErbB‐3 resulted positive in 51/81 (63.0%) of the ErbB‐4 positive cases and ErbB‐3/ErbB‐4 co‐expression was statistically significant (P = 0.0003). As expected, ErbB‐2 expression was associated with reduced overall survival at 15 years of follow‐up (P = 0.04), even after adjusting for a series of other prognostic factors (P = 0.05). Moreover, cumulative analysis of ErbB‐2/3/4 expression showed a strong positive association between higher total ErbB‐2/3/4 expression score and worse prognosis (P = 0.002). The simultaneous expression in cancer cells of more than one ErbB receptor identifies a subset of breast cancer patients at high risk for poor survival. J.Cell.Physiol.

PALB2 mutations in male breast cancer: a population-based study in Central Italy.

To the Editor, Male breast cancer (MBC) is a rare disease compared to female breast cancer (FBC). However, MBC shares many similarities with FBC, including genetic predisposition factors such as BRCA1/2 mutations. The frequency of BRCA1/2 mutations is quite different in ethnically diverse populationand clinic-based MBC series, ranging between 4 and 40% for BRCA2 and up to 10% for BRCA1 [1]. In a population-based series of 108 MBCs from Central Italy, we reported that about 9% of MBCs were BRCA1/2 carriers [2], suggesting the contribution of additional susceptibility genes. Several studies identify PALB2 as a moderate-penetrance breast cancer (BC) susceptibility gene, accounting for about 1% of BRCA1/2 negative familial/early onset BCs [3, 4]. PALB2 mutations were found in families with both FBC and MBC cases, suggesting that PALB2 may be involved in MBC risk [3]. As for BRCA1/2, there are evidences that PALB2 might play a role in prostate cancer (PC) [5]. Interestingly, PC patients have an increased risk of BC [6] and, on the other hand, MBC patients show an increased risk of PC [7], suggesting that these tumours may share risk factors. The role of PALB2 in MBC predisposition is still largely unknown. An interesting evaluation about this latter is provided in the recent article by Sauty de Chalon et al. [8]. Yet in the above mentioned study PALB2 pathogenic mutations were not found in 25 MBCs belonging to 25 BRCA1/2 negative families and, based on PALB2 mutation frequency (*1%), it cannot be excluded that these findings may indeed be due to the small series analysed. By using direct sequencing, we performed a screen for germline mutations of PALB2 coding region and intron– exon boundaries in 97 BRCA1/2 negative MBCs, previously identified in a population-based series of 108 MBCs [2]. Age at first BC diagnosis ranged between 35 and 90 years (mean 63.9 years), 25.8% of the patients reported a first-degree family history (FH) of breast/ovarian cancer and 14.4% had a personal history of cancer(s) at sites other than breast. In particular, prostate (28.5%) and bladder (28.5%) carcinomas were the most frequently observed metachronous cancers. Table 1 shows all the PALB2 variants identified in our study. No truncating mutations were found. A novel missense variant, I1180T, was identified in a young man diagnosed with BC at 42 years of age and with negative FH. In silico analysis (PolyPhen, SIFT, Align-GVGD and Pmut) showed that I1180T is likely to be deleterious, since it occurs in the WD40-4 conserved domain that regulates PALB2 interaction with BRCA2. This variant was not found in 90 male population controls analysed (Table 1). Three additional missense variants (Q559R, E672Q and G998E) and one synonymous (T1100T) variant, all previously Valentina Silvestri and Piera Rizzolo equally contributed to the work.

Association between the BRCA2 N372H variant and male breast cancer risk: a population-based case-control study in Tuscany, Central Italy

BackgroundMale breast cancer (MBC) is a rare disease and little is known about its aetiology. Germ-line mutations of BRCA2 and, at lower frequency, of BRCA1 are implicated in a relatively small proportion of MBC cases. Common polymorphic variants in BRCA1 and BRCA2 genes may represent breast cancer (BC) susceptibility alleles and could be associated with a modestly increased risk of MBC at population level. Considering the relevant role of BRCA2 in MBC, we investigated whether the BRCA2 N372H variant, representing the only common non-synonymous polymorphism in BRCA2, might modulate the risk of BC in male populations.MethodsA case-control study was performed comparing a population-based series of 99 MBC cases, characterized for BRCA1 and BRCA2 mutations, with 261 male population controls, all residing in Tuscany, Central Italy. All MBC cases and controls were genotyped for the BRCA2 N372H allele by TaqMan allelic discrimination assays. To evaluate the genotype specific risk of the BRCA2 N372H variant, MBC carriers of germ-line BRCA1/2 mutations were excluded from the analyses.ResultsNo association emerged in univariate and age-adjusted analyses. Age-specific analyses suggested an increased risk for the HH homozygous genotype in subjects younger than 60 years. A statistically significant interaction emerged between this genotype and age (p = 0.032). When analyses were restricted to MBC cases enrolled in the first 4 years following diagnosis, a recessive model showed a significantly increased risk of MBC in HH subjects younger than 60 years (OR = 5.63; 95% CI = 1.70;18.61).ConclusionOverall, our findings, although based on a relatively small series, suggest that the BRCA2 HH homozygous genotype might be positively associated with an increased risk of MBC in men younger than 60 years.

Mutation screening of RAD51C in male breast cancer patients

We read with great interest the paper by Akbari and colleagues [1] in a recent issue of Breast Cancer Research. The authors reported on the absence of RAD51C mutations in 454 patients with BRCA1/2-negative familial breast cancer/ovarian cancer (BC/OC). In the initial report by Meindl and colleagues [2], RAD51C mutations were identified in 6 out of 480 patients with BRCA1/2-negative familial BC/OC. Interestingly, on the basis of histopathologic features, including intermediate grade (G2), estrogen receptor-positive (ER+), progesterone receptor-positive (PR+), and HER2-negative (HER2-) expression, RAD51C-associated BCs were found to be similar to BRCA2-associated BCs [2]. BRCA2 is known to play a significant role in male BC (MBC); however, no occurrence of MBC was observed in the six RAD51C families described [2]. To investigate the role of RAD51C in MBC, we screened for RAD51C mutations in 97 MBC patients selected from our population-based series of 126 cases because they were previously found negative for BRCA1/2, CHEK2, PALB2, and BRIP1 mutations [3,4]. Notably, 25.8% of cases showed a positive first-degree family history of BC or OC or both. The majority of MBCs were invasive ductal carcinomas (74.5%), G2 (53.5%), ER+ (90.7%), PR+ (82.6%), or HER2- (85.4%). Overall, 66% of the MBCs showed an ER+/PR+/HER2- phenotype. All patients provided informed consent to the study. We carried out mutation screening of the nine exons and intron/exon boundaries of RAD51C by high resolution melting (HRM) analysis, a rapid closed-tube mutation scanning method with high sensitivity and specificity. Cases displaying abnormal profiles were evaluated by direct sequencing. Primers are available upon request. We found no truncating RAD51C mutations. We identified a novel intronic variant, IVS3 c.738-16G>T, in 1 out of 97 MBCs (1%). By in silico analysis, performed with Splice Site Prediction (BDGP, Berkeley Drosophila Genome Project, Lawrence Berkeley National Laboratory, Berkeley, CA, USA) and NetGene 2 Server software (CBSA, Center for Biological Sequence Analysis, Technical University of Denmark, Lyngby, Denmark), the IVS3 c.738-16G>T variant is predicted not to affect splicing. This variant was also identified in 2 out of 173 (1.2%) population controls examined. We also found a neutral polymorphic intronic variant, IVS6 c.904+34T>C (rs28363318), in 16 out of 97 (16.5%) MBCs. Overall, our results, which are based on a relatively large MBC series, are consistent with the findings by Akbari and colleagues [1] and with data on 92 patients with hereditary gynecological cancer in which no deleterious RAD51C mutations were identified [5] and would suggest that the impact of RAD51C mutations on BC predisposition might be more limited than initially reported. In conclusion, we found no evidence that RAD51C mutations may contribute to MBC susceptibility. Further studies on larger MBC series are needed to confirm our findings.

Founder mutations account for the majority of BRCA1-attributable hereditary breast/ovarian cancer cases in a population from Tuscany, Central Italy

Background Germline mutations in the BRCA1 and BRCA2 tumour-suppressor genes predispose to early-onset breast and ovarian cancer. Although both genes display a highly heterogeneous mutation spectrum, a number of alterations recur in some populations. Only a limited number of founder mutations have been identified in the Italian population so far. Objective To investigate the spectrum of BRCA1/BRCA2 mutations in a set of families originary from the Central–Eastern part of Tuscany and to ascertain the presence of founder effects. We also wanted to approximate the age of the most frequent BRCA1 founder mutation. Results Overall, four distinct BRCA1 mutations accounted for a large fraction (72.7%) of BRCA1-attributable hereditary breast/ovarian cancer in families originary from this area. We identified common haplotypes for two newly recognised recurrent BRCA1 mutations, c.3228_3229delAG and c.3285delA. The c.3228_3229delAG mutation was estimated to have originated about 129 generations ago. Interestingly, male breast cancer cases were present in 3 out of 11 families with the c.3228_3229delAG mutation. Conclusions The observation that a high proportion of families with BRCA1 alterations from Central–Eastern Tuscany harbours a limited number of founder mutations can have significant impact on clinical management of at risk subjects from this area. In addition, the identification of a large set of families carrying an identical mutation that predisposes to breast and ovarian cancer provides unique opportunities to study the effect of other genetic and environmental factors on penetrance and disease phenotype.

Instability at sequence repeats in melanocytic tumours.

To obtain information on the prevalence of microsatellite mutations in melanomas, we analysed the status of 14 repetitive loci characterized by structurally different non-coding and coding sequence repeats in a panel of 34 primary melanocytic tumours and in lymph node metastases matched to 13 cases. Instability at one or more of the non-coding dinucleotide repeats D2S123, D3S1611, D5S107 and D18S34 was detected in ten out of the 34 primary tumours (29%) and in ten of the 13 metastases (77%). There was no instability at the non-coding mononucleotide repeats BAT25, BAT26 and AP Δ3 or at the coding mononucleotide runs within the TGF βRII, IGFIIR, BAX, hMSH3 and hMSH6 genes. A five-repeats expansion of the coding E2F4 (CAG)n run was found in the only malignant melanoma of soft parts examined, which also showed instability at two dinucleotide loci, and in a superficial spreading melanoma, which was stable at the mononucleotide and dinucleotide repeats but was the only tumour that manifested instability at the SCA1 (CAG)n repeat. The absence of mutations at mononucleotide tracts indicates that, in the malignant melanomas tested, microsatellite instability was not associated with the microsatellite mutator phenotype characteristic of mismatch repair-deficient tumours. On the other hand, our results confirm that microsatellite instability at dinucleotide repeats increases with melanoma progression, and indicate that expansions of triplet repeats may occur in melanocytic tumours.