Poly(ADP-ribose) polymerase inhibitors (PARPis) have demonstrated remarkable efficacy in tumors carrying BRCA1/2 pathogenic variants (PVs) through the mechanism of synthetic lethality. PVs in other homologous recombination (HR) genes may also impair homologous recombination repair and confer sensitivity to PARPis; however, their predictive value remains uncertain and appears to vary according to the affected gene and tumor type. We review and critically discuss the current evidence regarding the predictive value of non-BRCA HR gene pathogenic variants as biomarkers of PARPi sensitivity across ovarian, breast, prostate, and pancreatic cancers. A narrative review was conducted between October 2023 and December 2025, first identifying pivotal clinical trials of PARP inhibitors across ovarian, breast, prostate, and pancreatic cancers, followed by a targeted search of PubMed, Embase, Web of Science, and Google Scholar for relevant preclinical and clinical studies. Seventeen clinical studies and multiple preclinical reports were analyzed regarding genomic frequency, HRD association, and treatment response. Preclinical studies consistently demonstrated increased PARPi sensitivity in models with alterations in several non-BRCA HR genes. Clinical evidence, however, was heterogeneous. PALB2 demonstrated the strongest and most consistent association with PARPi benefit across tumor types, while RAD51C and RAD51D also showed clinically meaningful activity, particularly in ovarian cancer. In contrast, evidence supporting PARPi sensitivity in tumors harboring ATM, CHEK2, CDK12, and several other HR gene alterations remained limited or inconsistent. Differences in gene function, biallelic inactivation, variant type, and current limitations of HRD companion diagnostic assays likely contribute to the observed variability in clinical response. Non-BRCA HR gene alterations represent promising predictive biomarkers for PARPi therapy but should not be considered a homogeneous group. Future biomarker-driven studies integrating comprehensive genomic profiling and functional assessment of homologous recombination deficiency are needed to refine patient selection and optimize the clinical application of PARPis beyond BRCA1/2-associated cancers.

Introduction: High-throughput sequencing techniques have revolutionized oncology. Paired germline-tumor DNA analysis has emerged as a comprehensive strategy to uncover actionable alterations in advanced cancer patients (ACP) enrolled in precision oncology trials. However, challenges persist in variant interpretation and managing incidental germline findings. Methods: We conducted a study involving 288 ACP from MOSCATO (NCT01566019) and MATCHR (NCT02517892) trials to assess germline variants impacting cancer-related genes. Germline DNA sequencing was performed using a panel of 250 cancer-related genes, and the results were discussed during tumor molecular board sessions. Results: Germline pathogenic variants (PV) were classified according to the ESCAT classification. Lung cancer (36.8 %), followed by prostate (18.4 %) and breast cancer (17.7 %), comprised the most prevalent tumor types. PVs were found in 12.5 % of patients. Most PVs were classified as ESCAT X (63.9 %), highlighting limited therapeutic actionability. Notably,2 % of patients had actionable variants (ESCAT I-A/II-A). Incidental findings included 7.3 % of patients with PVs in cancer-predisposition genes, with 2.4 % having very high-risk potential, necessitating mandatory oncogenetic counseling. Nearly one in five patients (21.9 %) had at least one VUS. Discussion: Our study underscores the significance of germline sequencing in identifying actionable alterations and the need for improved variant interpretation as well as pretest counseling plans in precision oncology trials.

MicroRNAs (miRNAs) are highly deregulated in cancer and play a role in the initiation of tumorigenesis. Recently, miRNAs have attracted attention in gastrointestinal (GI) cancers. Single nucleotide polymorphisms (SNPs) could affect the genes involved in each step of miRNA biosynthesis. Several meta-analyses of case-control studies have assessed the association between miRNA "pathway" gene-SNPs (including biosynthesis regulators and binding sites) and susceptibility to GI cancers. We present in this mini-review the current knowledge on the association between miRNAs "pathway" genes and GI cancer predisposition. The interaction between miRNA/regulators/binding site-SNPs and environmental as well as genomic factors is an interesting field that should be exploited in future studies.