Population-based BRCA1/2 testing programmes are highly acceptable in the Jewish community: results of the JeneScreen Study.

BACKGROUND: Ashkenazi Jewish (AJ) people have a higher incidence of BRCA1/2 pathogenic variants (PVs) than unselected populations. Three BRCA-Jewish founder mutations (B-JFMs) comprise >90% of BRCA1/2 PVs in AJ people. Personal/family cancer history-based testing misses ≥50% of people with B-JFM. METHODS: We compared two population-based B-JFM screening programmes in Australia-using (1) an online tool (Sydney) and (2) in-person group sessions (Melbourne). RESULTS: Of 2167 Jewish people tested (Sydney n=594; Melbourne n=1573), 1.3% (n=28) have a B-JFM, only 2 of whom had a significant cancer family history (Manchester score ≥12). Pretest anxiety scores were normal (mean 9.9±3.5 (6-24)), with no significant post-result change (9.5±3.3). Decisional regret (mean 7.4±13.0 (0-100)), test-related distress (mean 0.8+/2.2 (0-30)) and positive experiences (reverse-scored) (mean 3.4±4.5 (1-20)) scores were low, with no significant differences between Sydney and Melbourne participants. Post-education knowledge was good overall (mean 11.8/15 (±2.9)) and significantly higher in Melbourne than Sydney. Post-result knowledge was the same (mean 11.7 (±2.4) vs 11.2 (±2.4)). Participants with a B-JFM had higher post-result anxiety and test-related distress and lower positive experiences, than those without a B-JFM, but scores were within the normal range. Family cancer history did not significantly affect knowledge or anxiety, or pretest perception of B-JFM or cancer risks. Most participants (93%) were satisfied/very satisfied with the programme. CONCLUSION: Both B-JFM screening programmes are highly acceptable to Australian Jewish communities. The programme enabled identification of several individuals who were previously unaware they have a B-JFM, many of whom would have been ineligible for current criteria-based testing in Australia.

Somatic inactivation of breast cancer predisposition genes in tumors associated with pathogenic germline variants.

BACKGROUND: Breast cancers (BCs) that arise in individuals heterozygous for a germline pathogenic variant in a susceptibility gene, such as BRCA1 and BRCA2, PALB2, and RAD51C, have been shown to exhibit biallelic loss in the respective genes and be associated with triple-negative breast cancer (TNBC) and distinctive somatic mutational signatures. Tumor sequencing thus presents an orthogonal approach to assess the role of candidate genes in BC development. METHODS: Exome sequencing was performed on paired normal-breast tumor DNA from 124 carriers of germline loss-of-function (LoF) or missense variant carriers in 15 known and candidate BC predisposition genes identified in the BEACCON case-control study. Biallelic inactivation and association with tumor genome features including mutational signatures and homologous recombination deficiency (HRD) score were investigated. RESULTS: BARD1-carrying TNBC (4 of 5) displayed biallelic loss and associated high HRD scores and mutational signature 3, as did a RAD51D-carrying TNBC and ovarian cancer. Biallelic loss was less frequent in BRIP1 BCs (4 of 13) and had low HRD scores. In contrast to other established BC genes, BCs from carriers of CHEK2 LoF (6 of 17) or missense (2 of 20) variant had low rates of biallelic loss. Exploratory analysis of BC from carriers of LoF variants in candidate genes such as BLM, FANCM, PARP2, and RAD50 found little evidence of biallelic inactivation. CONCLUSIONS: BARD1 and RAD51D behave as classic BRCA-like predisposition genes with biallelic inactivation, but this was not observed for any of the candidate genes. However, as demonstrated for CHEK2, the absence of biallelic inactivation does not provide definitive evidence against the gene's involvement in BC predisposition.

Evaluation of two population screening programmes for BRCA1/2 founder mutations in the Australian Jewish community: a protocol paper.

INTRODUCTION: People of Ashkenazi Jewish (AJ) ancestry are more likely than unselected populations to have a BRCA1/2 pathogenic variant, which cause a significantly increased risk of breast, ovarian and prostate cancer. Three specific BRCA1/2 pathogenic variants, referred to as BRCA-Jewish founder mutations (B-JFM), account for >90% of BRCA1/2 pathogenic variants in people of AJ ancestry. Current practice of identifying eligible individuals for BRCA testing based on personal and/or family history has been shown to miss at least 50% of people who have one of these variants. Here we describe the protocol of the JeneScreen study-a study established to develop and evaluate two different population-based B-JFM screening programmes, offered to people of Jewish ancestry in Sydney and Melbourne, Australia. METHODS AND ANALYSIS: To rmeasure the acceptability of population-based B-JFM screening in Australia, two screening programmes using different methodologies have been developed. The Sydney JeneScreen programme provides information and obtains informed consent by way of an online tool. The Melbourne JeneScreen programme does this by way of community sessions attended in person. Participants complete questionnaires to measure clinical and psychosocial outcomes at baseline, and for those who have testing, 2 weeks postresult. Participants who decline testing are sent a questionnaire regarding reasons for declining. Participants with a B-JFM are sent questionnaires 12-month and 24-month post-testing. The questionnaires incorporate validated scales, which measure anxiety, decisional conflict and regret, and test-related distress and positive experiences, and other items specifically developed or adapted for the study. These measures will be assessed for each programme and the two population-based B-JFM screening methods will be compared. ETHICS AND DISSEMINATION: Institutional Human Research Ethics Committee approval was obtained from the South Eastern Area Health Service Human Research Ethics Committee: HREC Ref 16/125.Following the analysis of the study results, the findings will be disseminated widely through conferences and publications, and directly to participants in writing.

The prognostic significance of immune microenvironment in breast ductal carcinoma in situ.

BACKGROUND: The role of different subtypes of tumour infiltrating lymphocytes (TILs) in breast ductal carcinoma in situ (DCIS) is still poorly defined. This study aimed to assess the prognostic significance of B and T lymphocytes and immune checkpoint proteins expression in DCIS. METHODS: A well characterised DCIS cohort (n = 700) with long-term follow-up comprising pure DCIS (n = 508) and DCIS mixed with invasive carcinoma (IBC; n = 192) were stained immunohistochemically for CD20, CD3, CD4, CD8, FOXP3, PD1 and PDL1. Copy number variation and TP53 mutation status were assessed in a subset of cases (n = 58). RESULTS: CD3+ lymphocytes were the predominant cell subtype in the pure DCIS cohort, while FOXP3 showed the lowest levels. PDL1 expression was mainly seen in the stromal TILs. Higher abundance of TILs subtypes was associated with higher tumour grade, hormone receptor negativity and HER2 positivity. Mutant TP53 variants were associated with higher levels of stromal CD3+, CD4+ and FOXP3+ cells. DCIS coexisting with invasive carcinoma harboured denser stromal infiltrates of all immune cells and checkpoint proteins apart from CD4+ cells. Stromal PD1 was the most differentially expressed protein between DCIS and invasive carcinoma (Z = 5.8, p < 0.0001). Dense TILs, stromal FOXP3 and PDL1 were poor prognostic factors for DCIS recurrence, while dense TILs were independently associated with poor outcome for all recurrences (HR = 7.0; p = 0.024), and invasive recurrence (HR = 2.1; p = 0.029). CONCLUSIONS: Immunosuppressive proteins are potential markers for high risk DCIS and disease progression. Different stromal and intratumoural lymphocyte composition between pure DCIS, DCIS associated with IBC and invasive carcinoma play a potential role in their prognostic significance and related to the underlying genomic instability. Assessment of overall TILs provides a promising tool for evaluation of the DCIS immune microenvironment.

Resistance to ROS1 inhibition mediated by EGFR pathway activation in non-small cell lung cancer.

The targeting of oncogenic 'driver' kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we analyzed tumor samples from a patient who initially responded to the ROS1 inhibitor crizotinib but eventually developed acquired resistance. In addition, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78. Previously described mechanisms of acquired resistance to tyrosine kinase inhibitors including target kinase-domain mutation, target copy number gain, epithelial-mesenchymal transition, and conversion to small cell lung cancer histology were found to not underlie resistance in the patient sample or resistant cell line. However, we did observe a switch in the control of growth and survival signaling pathways from ROS1 to EGFR in the resistant cell line. As a result of this switch, ROS1 inhibition-resistant HCC78 cells became sensitive to EGFR inhibition, an effect that was enhanced by co-treatment with a ROS1 inhibitor. Our results suggest that co-inhibition of ROS1 and EGFR may be an effective strategy to combat resistance to targeted therapy in some ROS1 fusion-positive NSCLC patients.