Laboratory cross-comparison of tumor BRCA1/2 analysis in a multicenter epithelial ovarian cancer series: The BORNEO GEICO60-0 study

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Background: Epithelial ovarian cancer (EOC) identification of BRCA1 and BRCA2 mutations is usually carried out in germline, representing around 17% in high grade serous ovarian cancer (HGSOC) and further 5-7% are only identified in the tumor (somatic). The aim of this study was to identify in EOC tumor BRCA mutation frequency and inter-laboratory reproducibility using different Next-generation Sequencing (NGS) approaches. Methods: In an ambispective study design, a population of unselected consecutive non mucinous EOC was clinically annotated and Formalin-Fixed Paraffin-Embedded (FFPE) tumor BRCA1/2 mutation analysis was undertaken in two laboratories (Lab-1 and Lab-2) simultaneously. Both laboratories used their own validated NGS panels; variant allele frequency threshold was 5% for single nucleotide polymorphism and 10% for indels. Each laboratory classified variants into three categories based on ACMG criteria: non-mutated (class 1-2), Variants of Uncertain Significance (VUS: class 3) and likely pathogenic/pathogenic (class 4-5). Germline BRCA analysis was available according to local clinical practice or centralized in Lab-1 if histology was low grade. Results: Ninety FFPE samples were received, 8 had insufficient material to be analyzed in both laboratories and 6 cases were discarded due to tumor cellularity below 20% leaving 76 cases to be sequenced. The population had a median age of 58 (25-84) years, 87% (66/76) of HGSOC histology and 70% of advanced stages (III-IVB: 53) and 14.5% (11) germline BRCA mutations (3 with not available results). Lab-1 identified 17 class 4-5 mutations, 11 correspond to germline, 4 (5.3%) are just somatic and 2 have germline results not available yet. Lab-2 had one not valuable analysis and identified 16 class 4-5 mutations, 10 corresponding to germline and 4 somatic variants. Percentage of concordance between both laboratories was 96% (kappa coefficient 0.883; p value < 0.0001). Three discordant out of 18 class 4-5 mutations included 2 undetected (VAF of 14.9% and 60.3% respectively) and one class 4 in Lab-2 classified as VUS in Lab-1 due to different interpretation criteria. Conclusions: The global BRCA mutation frequency in our series was 22.3% for Lab-1 and 21.0% for Lab-2. Concordance between tumor BRCA mutation analysis was high (96%). Nevertheless, further effort is required on harmonizing the technical and analytical aspects in tumor mutational analysis.

Cancer-associated fibroblasts and M2-polarized macrophages synergize during prostate carcinoma progression

Inflammation is now acknowledged as an hallmark of cancer. Cancer-associated fibroblasts (CAFs) force a malignant cross talk with cancer cells, culminating in their epithelial-mesenchymal transition and achievement of stemness traits. Herein, we demonstrate that stromal tumor-associated cells cooperate to favor malignancy of prostate carcinoma (PCa). Indeed, prostate CAFs are active factors of monocyte recruitment toward tumor cells, mainly acting through stromal-derived growth factor-1 delivery and promote their trans-differentiation toward the M2 macrophage phenotype. The relationship between M2 macrophages and CAFs is reciprocal, as M2 macrophages are able to affect mesenchymal-mesenchymal transition of fibroblasts, leading to their enhanced reactivity. On the other side, PCa cells themselves participate in this cross talk through secretion of monocyte chemotactic protein-1, facilitating monocyte recruitment and again macrophage differentiation and M2 polarization. Finally, this complex interplay among cancer cells, CAFs and M2 macrophages, cooperates in increasing tumor cell motility, ultimately fostering cancer cells escaping from primary tumor and metastatic spread, as well as in activation of endothelial cells and their bone marrow-derived precursors to drive de novo angiogenesis. In keeping with our data obtained in vitro, the analysis of patients affected by prostate cancers at different clinical stages revealed a clear increase in the M2/M1 ratio in correlation with clinical values. These data, coupled with the role of CAFs in carcinoma malignancy to elicit expression of stem-like traits, should focus great interest for innovative strategies aimed at the co-targeting of inflammatory cells and fibroblasts to improve therapeutic efficacy.