Hirschsprung disease (HSCR, OMIM 142623) is a developmental disorder characterized by the absence of ganglion cells along variable lengths of the distal gastrointestinal tract, which results in tonic contraction of the aganglionic gut segment and functional intestinal obstruction. The RET proto-oncogene is the major gene for HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. Many other genes have been described to be associated with the pathology, as NRG1 gene (8p12), encoding neuregulin 1, which is implicated in the development of the enteric nervous system (ENS), and seems to contribute by both common and rare variants. Here we present the results of a comprehensive analysis of the NRG1 gene in the context of the disease in a series of 207 Spanish HSCR patients, by both mutational screening of its coding sequence and evaluation of 3 common tag SNPs as low penetrance susceptibility factors, finding some potentially damaging variants which we have functionally characterized. All of them were found to be associated with a significant reduction of the normal NRG1 protein levels. The fact that those mutations analyzed alter NRG1 protein would suggest that they would be related with HSCR disease not only in Chinese but also in a Caucasian population, which reinforces the implication of NRG1 gene in this pathology.

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Hirschsprung disease (HSCR) is attributed to a failure of neural crest derived cells to migrate, proliferate, differentiate or survive in the bowel wall during embryonic Enteric Nervous System (ENS) development. This process requires a wide and complex variety of molecules and signaling pathways which are activated by transcription factors. In an effort to better understand the etiology of HSCR, we have designed a study to identify new transcription factors participating in different stages of the colonization process. A differential expression study has been performed on a set of transcription factors using Neurosphere-like bodies from both HSCR and control patients. Differential expression levels were found for CDYL, MEIS1, STAT3 and PAX6. A significantly lower expression level for PAX6 in HSCR patients, would suit with the finding of an over-representation of the larger tandem (AC)m(AG)n repeats within the PAX6 promoter in HSCR patients, with the subsequent loss of protein P300 binding. Alternatively, PAX6 is a target for DNMT3B-dependant methylation, a process already proposed as a mechanism with a role in HSCR. Such decrease in PAX6 expression may influence in the proper function of signaling pathways involved in ENS with the confluence of additional genetic factors to the manifestation of HSCR phenotype.

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Background: Small cell lung cancer (SCLC) is one of the greatest therapeutic challenges of oncology. Potential associations between single nucleotide polymorphisms in heat shock protein β1 (HSPB1) and transforming growth factor β1 (TGFβ1) and survival have been investigated. Methods: A prospective multicenter study of 94 patients with SCLC treated between 2013 and 2016 was conducted. Clinical, tumour-related, therapeutic, and genetic (9 SNPs of TGFβ1 gene and 5 of HSPB1 gene) variables were analyzed. Results: The cohort included 77 men and 17 women with a median age of 61 years. Eighty percent presented with limited stage at diagnosis and received thoracic radiation with a median dose of 45 Gy (twice-daily radiation in 42%). Forty-seven percent received concurrent platinum-based chemotherapy and 57% received prophylactic cranial irradiation (PCI). Overall survival (OS) was 34% at 2 years and 16% at 3 years. In multivariate analysis, the rs4803455:CA genotype of the TGFβ1 gene showed a statistically significant association with lower disease-free survival (DFS; hazard ratio [HR] 3.13; confidence interval [CI] 1.19–8.17; p = 0.020) and higher local recurrence (HR 3.80; CI 1.37–10.5; p = 0.048), and a marginal association with lower OS (HR 1.94; CI 0.98–3.83; p = 0.057). A combined analysis showed that patients receiving PCI and carrying the rs4803455:CA genotype had statistically significant lower OS ( p < 0.001) and DFS ( p < 0.001) than patients receiving PCI and carrying the rs4803455:AA genotype. Conclusions: Genetic analysis showed the CA genotype of TGFβ1 SNP rs4803455 was associated with worse prognosis in patients with SCLC and could be considered as a potential biomarker.

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e21038 Background: Small cell lung cancer (SCLC) is one of the greatest therapeutic challenges of oncology. Potential associations between single-nucleotide polymorphisms (SNP) in Heat shock protein beta- 1 (HSPB1) and Transforming growth factor (TGFß1) and survival have been investigated. Methods: A prospective multicenter study of 94 SCLC patients treated between 2013 and 2016 was conducted. Several variables clinical, tumour-related, therapeutic, and genetic (9 SNPs of TGFß1 gene and 5 of HSPB1 gene) variables were analyzed. Results: The cohort included 77 men and 17 women with a median age of 61 years. Eighty percent presented with limited stage at diagnosis and received thoracic radiation with a median dose of 45 Gy (BID in 42%). Forty-seven percent received concomitant platinum-based chemotherapy and 57% received prophylactic cranial irradiation (PCI). Overall survival (OS) was 34% at 2 years and 16% at 3 years. In multivariate analysis PCI and the TGFß1 SNP rs4803455 showed a statistically significant association with OS and local control. Patients with the CA genotype of the TGFß1 SNP rs4803455 showed worse OS (HR 2.53; IC 1.22-5.21; p = 0.012) and higher local recurrence (HR 2.26; IC 1.01-5.08;p = 0.048). A combined analysis showed that those patients receiving PCI and carrying the rs4803455:CA genotype had a statistically significant lower OS (p < 0.001) and disease-free survival (p < 0.001) than patients receiving PCI and carrying the rs4803455:AA genotype. Conclusions: Genetic analysis showed that the CA genotype of TGFß1 SNP rs4803455 was associated with worse prognosis in SCLC patients and could be considered as a potential biomarker for OS.