Ultrastructural, cytogenetic, and molecular findings in mast cell leukemia : Case report

We report a de novo aleukemic form of MCL with a complex monosomic karyotype with LOH for multiple chromosomes and TP53 mutation. Additionally, whereas D816V KIT was not found, the c-Kit transmembrane domain p.M541L variant was detected which is the most common SNP of KIT gene in humans with controversial pathogenic role. In these cases, it is crucial to perform a rapid broad molecular study for an accurate diagnosis which could help to initiate targeted therapy

Decay in survival motor neuron and plastin 3 levels during differentiation of iPSC-derived human motor neurons

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by mutations in Survival Motor Neuron 1 (SMN1), leading to degeneration of alpha motor neurons (MNs) but also affecting other cell types. Induced pluripotent stem cell (iPSC)-derived human MN models from severe SMA patients have shown relevant phenotypes. We have produced and fully characterized iPSCs from members of a discordant consanguineous family with chronic SMA. We differentiated the iPSC clones into ISL-1+/ChAT+ MNs and performed a comparative study during the differentiation process, observing significant differences in neurite length and number between family members. Analyses of samples from wild-type, severe SMA type I and the type IIIa/IV family showed a progressive decay in SMN protein levels during iPSC-MN differentiation, recapitulating previous observations in developmental studies. PLS3 underwent parallel reductions at both the transcriptional and translational levels. The underlying, progressive developmental decay in SMN and PLS3 levels may lead to the increased vulnerability of MNs in SMA disease. Measurements of SMN and PLS3 transcript and protein levels in iPSC-derived MNs show limited value as SMA biomarkers

Increased signalling of EGFR and IGF1R, and deregulation of PTEN/PI3K/Akt pathway are related with trastuzumab resistance in HER2 breast carcinomas

Trastuzumab resistance hampers its well-known efficacy to control HER2-positive breast cancer. The involvement of PI3K/Akt pathway in this mechanism is still not definitively confirmed. We selected 155 patients treated with trastuzumab after development of metastasis or as adjuvant/neoadjuvant therapy. We performed immunohistochemistry for HER2, ER/PR, epidermal growth factor 1-receptor (EGFR), α -insulin-like growth factor 1-receptor (IGF1R), phosphatase and tensin homologue (PTEN), p110 α, pAkt, pBad, pmTOR, pMAPK, MUC1, Ki67, p53 and p27; mutational analysis of PIK3CA and PTEN, and PTEN promoter hypermethylation. We found 46% ER/PR-positive tumours, overexpression of EGFR (15%), α -IGF1R (25%), p110 α (19%), pAkt (28%), pBad (22%), pmTOR (23%), pMAPK (24%), MUC1 (80%), PTEN loss (20%), and PTEN promoter hypermethylation (20%). PIK3CA and PTEN mutations were detected in 17% and 26% tumours, respectively. Patients receiving adjuvant trastuzumab with α -IGF1R or pBad overexpressing tumours presented shorter progression-free survival (PFS) (all P ⩽0.043). Also, p110 α and mTOR overexpression, liver and brain relapses implied poor overall survival (OS) (all P ⩽0.041). In patients with metastatic disease, decreased PFS correlated with p110 α expression (P =0.024), whereas for OS were the presence of vascular invasion and EGFR expression (P ⩽0.019; Cox analysis). Our results support that trastuzumab resistance mechanisms are related with deregulation of PTEN/PI3K/Akt/mTOR pathway, and/or EGFR and IGF1R overexpression in a subset of HER2-positive breast carcinomas

Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors

Background: Inherited mutations in the BRCA1 gene may be responsible for al-most half of inherited breast carcino-mas. However, somatic (acquired) mu-tations in BRCA1 have not been reported, despite frequent loss of het-erozygosity (LOH or loss of one copy of the gene) at the BRCA1 locus and loss of BRCA1 protein in tumors. To ad-dress whether BRCA1 may be inacti-vated by pathways other than muta-tions in sporadic tumors, we analyzed the role of hypermethylation of the gene’s promoter region. Methods: Methylation patterns in the BRCA1 promoter were assessed in breast can-cer cell lines, xenografts, and 215 pri-mary breast and ovarian carcinomas by methylation-specific polymerase chain reaction (PCR). BRCA1 RNA ex-pression was determined in cell lines and seven xenografts by reverse tran-scription–PCR. P values are two-sided. Results: The BRCA1 promoter was found to be unmethylated in all normal tissues and cancer cell lines tested. However, BRCA1 promoter hyper-methylation was present in two breast cancer xenografts, both of which had loss of the BRCA1 transcript. BRCA1 promoter hypermethylation was pres-ent in 11 (13%) of 84 unselected pri-mary breast carcinomas. BRCA1 meth-ylation was strikingly associated with the medullary (67 % methylated; P =.0002 versus ductal) and mucinous (55 % methylated; P =.0033 versus duc-tal) subtypes, which are overrepre-sented in BRCA1 families. In a second series of 66 ductal breast tumors infor-mative for LOH, nine (20%) of 45 tu-mors with LOH had BRCA1 hyper-methylation, while one (5%) of 21 without LOH was methylated (P =.15). In ovarian neoplasms, BRCA1 methyl-ation was found only in tumors with LOH, four (31%) of 13 versus none of 18 without LOH (P =.02). The BRCA1 promoter was unmethylated in other tumor types. Conclusion: Silencing of the BRCA1 gene by promoter hyper-methylation occurs in primary breast and ovarian carcinomas, especially in the presence of LOH and in specific histopathologic subgroups. These find-ings support a role for this tumor sup-pressor gene in sporadic breast and ovarian tumorigenesis. [J Natl Cance

Ultrastructural, cytogenetic, and molecular findings in mast cell leukemia : Case report

We report a de novo aleukemic form of MCL with a complex monosomic karyotype with LOH for multiple chromosomes and TP53 mutation. Additionally, whereas D816V KIT was not found, the c-Kit transmembrane domain p.M541L variant was detected which is the most common SNP of KIT gene in humans with controversial pathogenic role. In these cases, it is crucial to perform a rapid broad molecular study for an accurate diagnosis which could help to initiate targeted therapy