Chiara Chianese

Despite major advances in the treatment of metastatic colorectal cancer (mCRC), the survival rate remains very poor. This study aims at exploring the prognostic value of RAS‐mutant allele fraction (MAF) in plasma in mCRC. Forty‐seven plasma samples from 37 RAS‐mutated patients with nonresectable metastases were tested for RAS in circulating tumor DNA using BEAMing before first‐ and/or second‐line treatment. RAS MAF was correlated with several clinical parameters (number of metastatic sites, hepatic volume, carcinoembryonic antigen, CA19‐9 levels, primary site location, and treatment line) and clinical outcome [progression‐free survival (PFS) and overall survival (OS)]. An independent cohort of 32 patients from the CAPRI‐GOIM trial was assessed for clinical outcome based on plasma baseline MAF. RAS MAF analysis at baseline revealed a significant correlation with longer OS [Hazard ratios (HR) = 3.514; P = 0.00066]. Patients with lower MAF also showed a tendency to longer PFS, although not statistically significant. Multivariate analysis showed RAS MAFs as an independent prognostic factor in both OS (HR = 2.73; P = 0.006) and first‐line PFS (HR = 3.74; P = 0.049). Tumor response to treatment in patients with higher MAF was progression disease (P = 0.007). Patients with low MAFs at baseline in the CAPRI‐GOIM group also showed better OS [HR = 3.84; 95% confidence intervals (CI) 1.5–9.6; P = 0.004] and better PFS (HR = 2.5; 95% CI: 1.07–5.62; P = 0.033). This minimally invasive test may help in adding an independent factor to better estimate outcomes before initiating treatment. Further prospective studies using MAF as a stratification factor could further validate its utility in clinical practice.

Spermatogenesis is a highly complex process involving several thousand genes, only a minority of which have been studied in infertile men. In a previous study, we identified a number of Copy Number Variants (CNVs) by high-resolution array-Comparative Genomic Hybridization (a-CGH) analysis of the X chromosome, including 16 patient-specific X chromosome-linked gains. Of these, five gains (DUP1A, DUP5, DUP20, DUP26 and DUP40) were selected for further analysis to evaluate their clinical significance. The copy number state of the five selected loci was analyzed by quantitative-PCR on a total of 276 idiopathic infertile patients and 327 controls in a conventional case-control setting (199 subjects belonged to the previous a-CGH study). For one interesting locus (intersecting DUP1A) additional 338 subjects were analyzed. All gains were confirmed as patient-specific and the difference in duplication load between patients and controls is significant (p = 1.65×10⁻⁴). Two of the CNVs are private variants, whereas 3 are found recurrently in patients and none of the controls. These CNVs include, or are in close proximity to, genes with testis-specific expression. DUP1A, mapping to the PAR1, is found at the highest frequency (1.4%) that was significantly different from controls (0%) (p = 0.047 after Bonferroni correction). Two mechanisms are proposed by which DUP1A may cause spermatogenic failure: i) by affecting the correct regulation of a gene with potential role in spermatogenesis; ii) by disturbing recombination between PAR1 regions during meiosis. This study allowed the identification of novel spermatogenesis candidate genes linked to the 5 CNVs and the discovery of the first recurrent, X-linked gain with potential clinical relevance.