Detecting prostate cancer (PCa) using non-invasive diagnostic markers still remains a challenge. The aim of this study was the identification of urine proteins that are sufficiently sensitive and specific to detect PCa in the early stages. Comparative proteomics profiling of urine from patients with PCa, benign prostate hyperplasia, bladder cancer, and renal cancer, coupled with bioinformatics analysis, were performed. Statistically significant difference in abundance showed 20 and 85 proteins in the 2-D DIGE/MS and label-free LC-MS/MS experiments, respectively. In silico analysis indicated activation, binding, and cell movement of subset of immune cells as the top affected cellular functions in PCa, together with the down-regulation of Acute Phase Response Signaling and Liver X Receptor/ Retinoid X Receptor (LXR/RXR) activation pathways. The most promising biomarkers were 35, altered in PCa when compared to more than one group. Half of these have confirmed localization in normal or PCa tissues. Twenty proteins (CD14, AHSG, ENO1, ANXA1, CLU, COL6A1, C3, FGA, FGG, HPX, PTGDS, S100A9, LMAN2, ITIH4, ACTA2, GRN, HBB, PEBP1, CTSB, SPP1) are oncogenes, tumor suppressors, and multifunctional proteins with highly confirmed involvement in PCa, while 9 (AZU1, IGHG1, RNASE2, PZP, REG1A, AMY1A, AMY2A, ACTG2, COL18A1) have been associated with different cancers, but not with PCa so far, and may represent novel findings. LC-MS/MS data are available via ProteomeXchange with identifier PXD008407.

Background: The spectrum of BRCA1 and BRCA2 mutations varies among populations; however, some mutations may be frequent in particular ethnic groups due to the “founder” effect. The c.3700_3704del mutation was previously described as a recurrent BRCA1 variant in Eastern European countries. This study aimed to investigate the frequency of c.3700_3704del BRCA1 mutation in Albanian breast and ovarian cancer patients from North Macedonia and Kosovo. Materials and methods: A total of 327 patients with invasive breast and/or ovarian cancer (111 Albanian women from North Macedonia and 216 from Kosovo) were screened for 13 recurrent BRCA1/2 mutations. Targeted NGS with a panel of 94 cancer-associated genes including BRCA1 and BRCA2 was performed in a selected group of 118 patients. Results: We have identified 21 BRCA1/2 pathogenic variants, 17 (14 BRCA1 and 3 BRCA2) in patients from Kosovo (7.9%) and 4 (1 BRCA1 and 3 BRCA2) in patients from North Macedonia (3.6%). All BRCA1/2 mutations were found in one patient each, except for c.3700_3704del BRCA1 mutation which was observed in 14 unrelated families, all except one originating from Kosovo. The c.3700_3704del mutation accounts for 93% of BRCA1 mutation positive cases and is present with a frequency of 6% among breast cancer patients from Kosovo. Conclusions: This is the first report of BRCA1/2 mutations among breast and ovarian cancer patients from Kosovo. The finding that BRCA1 c.3700_3704del represents a founder mutation in Kosovo with the highest worldwide reported frequency supports the implementation of fast and low-cost screening protocol, regardless of the family history and even a pilot population-based screening in at-risk population. Key words: BRCA1; c.3700_3704del; founder mutation; breast cancer; Kosovo Background: The spectrum of BRCA1 and BRCA2 mutations varies among populations; however, some mutations may be frequent in particular ethnic groups due to the “founder” effect. The c.3700_3704del mutation was previously described as a recurrent BRCA1 variant in Eastern European countries. This study aimed to investigate the frequency of c.3700_3704del BRCA1 mutation in Albanian breast and ovarian cancer patients from North Macedonia and Kosovo. Materials and methods: A total of 327 patients with invasive breast and/or ovarian cancer (111 Albanian women from North Macedonia and 216 from Kosovo) were screened for 13 recurrent BRCA1/2 mutations. Targeted NGS with a panel of 94 cancer-associated genes including BRCA1 and BRCA2 was performed in a selected group of 118 patients. Results: We have identified 21 BRCA1/2 pathogenic variants, 17 (14 BRCA1 and 3 BRCA2) in patients from Kosovo (7.9%) and 4 (1 BRCA1 and 3 BRCA2) in patients from North Macedonia (3.6%). All BRCA1/2 mutations were found in one patient each, except for c.3700_3704del BRCA1 mutation which was observed in 14 unrelated families, all except one originating from Kosovo. The c.3700_3704del mutation accounts for 93% of BRCA1 mutation positive cases and is present with a frequency of 6% among breast cancer patients from Kosovo. Conclusions: This is the first report of BRCA1/2 mutations among breast and ovarian cancer patients from Kosovo. The finding that BRCA1 c.3700_3704del represents a founder mutation in Kosovo with the highest worldwide reported frequency supports the implementation of fast and low-cost screening protocol, regardless of the family history and even a pilot population-based screening in at-risk population. Key words: BRCA1; c.3700_3704del; founder mutation; breast cancer; Kosovo

Background/Objectives: Expanded carrier screening (ECS) panels often rely on pan-ethnic databases, such as the ACMG Tier 3 panel, but their ability to capture population-specific reproductive risk is uncertain. We characterized pathogenic/likely pathogenic (P/LP) variants and at-risk-couple (ARC) probabilities in an underrepresented population from North Macedonia to inform ECS gene prioritization. Methods: NGS data from 1438 subjects of Macedonian, Albanian, and other local ancestry, referred for rare-disease diagnostics, were analyzed across 1795 candidate autosomal recessive/X-linked genes. P/LP variants were compared with gnomAD exomes v2.1.1 non-Finnish European frequencies (Fisher’s exact test). Gene-specific ARC probabilities ranked genes and generated cumulative ARC curves per subgroup. Results: We identified 2007 P/LP variants across 1096 genes. One hundred variants in 89 genes reached an allele frequency ≥ 1/200 in the Macedonian or Albanian subgroups; over one-third were absent from candidate ECS panels, mostly linked to severe or variable phenotypes. ARC saturated rapidly: genes with carrier counts ≥ 1/100 (ACMG Tier 2) accounted for over 85% of total ARC, and with ≥1/200 (ACMG Tier 3) for more than 93%. Total ARC among autosomal recessive panel genes (X-linked genes analyzed separately) was 3.42%, rising to 5.02% in the Albanian subgroup. Excluding top hypomorphic variants reduced ARC by 34–37%, highlighting variant-specific penetrance. The highest-ARC genes diverged between subgroups, with limited overlap with pan-ethnic panels. Conclusions: Population-specific carrier frequencies influence gene prioritization and estimated reproductive-risk probabilities for ECS. Population-tailored ECS panels that incorporate local carrier-frequency data, including embryonic/fetal-lethal genes, and account for hypomorphic alleles to avoid overestimating reproductive risk probabilities could improve the identification of couples at increased reproductive risk, particularly in underrepresented populations.