Prevalence of BRCA1 and BRCA2 pathogenic variants in 8627 unselected patients with breast cancer: stratification of age at diagnosis, family history and molecular subtype.

PURPOSE: Comprehensively analyzing the prevalence of BRCA1/2 germline pathogenic variants (PVs) in a large cohort of unselected Chinese patients with breast cancer has great clinical importance. METHODS: Germline pathogenic variants in full-length BRCA1/2 genes were determined through next-generation sequencing and/or Sanger sequencing assays in 8627 unselected Chinese patients with breast cancer who were treated at the Breast Center of Peking University Cancer Hospital. The prevalence of BRCA1/2 PVs was further stratified by age at diagnosis, family history of cancer and molecular subtype. RESULTS: We found that the overall prevalence of BRCA1/2 PVs was 6.0% in the entire cohort, 2.4% in BRCA1 and 3.7% in BRCA2. The prevalence of BRCA1/2 PVs in patients with early-onset breast cancer (age at diagnosis ≤ 40 years) was significantly higher than that in patients over the age of 40 (9.7% vs. 5.1%). The prevalence rates of BRCA1/2 PVs in patients with a family history of breast, ovarian, pancreatic, and prostate cancer were 19.5%, 39.0%, 11.1%, and 12.8%, respectively. Moreover, the number of relatives affected by breast cancer was associated with a higher prevalence of BRCA1/2 PVs. Molecular subtypes were associated with the prevalence of BRCA1/2 PVs. Patients with the triple-negative phenotype had the highest prevalence of BRCA1/2 PVs (13.3%) among the three molecular groups, followed by the HR + and HER2- group (5.9%), and the lowest was in the HER2 + group (2.5%). CONCLUSION: Our study provides the most comprehensive information to date on the prevalence of BRCA1/2 PVs in unselected Chinese patients with breast cancer.

Clinical relevance of pathogenic germline variants in mismatch repair genes in Chinese breast cancer patients.

The prevalence and clinical relevance of pathogenic germline variants in MMR genes have not been investigated in large series of breast cancers. In this study, we screened the germline variants in MMR genes in 8085 consecutive Chinese breast cancer patients, and investigated the MMR/PD-L1 protein expression and tumor mutation burden (TMB) of breast tumors from MMR variant carriers. We found that 15 of 8085 patients (0.19%) carried a pathogenic germline variant in MMR genes. Compared with non-carriers, MMR variant carriers might have worse recurrence-free survival (unadjusted hazard ratios [HR] = 2.70, 95% CI: 1.12-6.49, P = 0.027) and distant recurrence-free survival (unadjusted HR = 3.24, 95% CI: 1.45-7.22, P = 0.004). More importantly, some of the breast cancers from MMR carriers displayed MMR protein loss (5/13), TMB-high (2/10), and PD-L1 positive expression (9/13). This study showed that MMR variant carriers were rare in breast cancer. They might have worse survival and part of them might benefit from immunotherapy.

Paclitaxel-nanoparticles-loaded double network hydrogel for local treatment of breast cancer after surgical resection.

Anticancer drug-loaded hydrogels are a promising strategy for the local treatment of tumors such as breast cancer. We hypothesize that paclitaxel-nanoparticles-loaded double network (PTX-NPs-DN) hydrogel can deliver PTX locally and sustainably in the tumor resection cavity. In this study, hydrogels loaded with PTX-NPs were prepared via self-assembly of collagen and self-crosslinking of polyvinyl alcohol (PVA). The hydrogel with a porous structure has a compressive modulus of 33 kPa at a strain of 40%. In this system, PTX release presented a linear release kinetic over 10 days in vitro and higher accumulating concentrations of PTX in local adipose tissue than in plasma. The biocompatibility studies show that PTX-NPs-DN hydrogel did not induce cytotoxicity in different cell lines (MCF-7, L929s) and hemolysis in vitro nor inflammatory response in vivo. In vivo anti-tumor efficacy study, compared with all other groups, significantly decreased tumor weight and improved capacity to slow down tumor recurrences were observed in the group treated with PTX-NPs-DN hydrogel. In conclusion, this proof-of-concept study demonstrated the feasibility, tolerability and efficiency of PTX-NPs-DN hydrogel for the local treatment of breast cancer.

A rapid lung de-cellularization protocol supports embryonic stem cell differentiation in vitro and following implantation.

Pulmonary diseases represent a large portion of neonatal and adult morbidity and mortality. Many of these have no cure, and new therapeutic approaches are desperately needed. De-cellularization of whole organs, which removes cellular elements but leaves intact important extracellular matrix (ECM) proteins and three-dimensional architecture, has recently been investigated for ex vivo generation of lung tissues. As specific cell culture surfaces, including ECM composition, profoundly affect cell differentiation, this approach offers a potential means of using de-cellularized lungs to direct differentiation of embryonic and other types of stem/progenitor cells into lung phenotypes. Several different methods of whole-lung de-cellularization have been reported, but the optimal method that will best support re-cellularization and generation of lung tissues from embryonic stem cells (ESCs) has not been determined. We present a 24-h approach for de-cellularizing mouse lungs utilizing a detergent-based (Triton-X100 and sodium deoxycholate) approach with maintenance of three-dimensional lung architecture and ECM protein composition. Predifferentiated murine ESCs (mESCs), with phenotypic characteristics of type II alveolar epithelial cells, were seeded into the de-cellularized lung scaffolds. Additionally, we evaluated the effect of coating the de-cellularized scaffold with either collagen or Matrigel to determine if this would enhance cell adhesion and affect mechanics of the scaffold. Finally, we subcutaneously implanted scaffolds in vivo after seeding them with mESCs that are predifferentiated to express pro-surfactant protein C (pro-SPC). The in vivo environment supported maintenance of the pro-SPC-expressing phenotype and further resulted in vascularization of the implant. We conclude that a rapid detergent-based de-cellularization approach results in a scaffold that can maintain phenotypic evidence of alveolar epithelial differentiation of ESCs and support neovascularization after in vivo implantation.