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Variable expressivity of disease-associated variants implies a role for secondary variants that modify clinical features. We assessed the effects of modifier variants towards clinical outcomes of 2,252 individuals with primary variants. Among 132 families with the 16p12.1 deletion, distinct rare and common variant classes conferred risk for specific developmental features, including short tandem repeats for neurological defects and SNVs for microcephaly, while additional disease-associated variants conferred multiple genetic diagnoses. Within disease and population cohorts of 773 individuals with the 16p12.1 deletion, we found opposing effects of secondary variants towards clinical features across ascertainments. Additional analysis of 1,479 probands with other primary variants, such as 16p11.2 deletion and CHD8 variants, and 1,084 without primary variants, showed that phenotypic associations differed by primary variant context and were influenced by synergistic interactions between primary and secondary variants. Our study provides a paradigm to dissect the genomic architecture of complex disorders towards personalized treatment., Competing Interests: DECLARATION OF INTERESTS The authors declare no competing interests.

Enlargement of the cerebrospinal fluid (CSF)-filled brain ventricles (cerebral ventriculomegaly), the cardinal feature of congenital hydrocephalus (CH), is increasingly recognized among patients with autism spectrum disorders (ASD). KATNAL2, a member of Katanin family microtubule-severing ATPases, is a known ASD risk gene, but its roles in human brain development remain unclear. Here, we show that nonsense truncation of Katnal2 ( Katnal2Δ 17 ) in mice results in classic ciliopathy phenotypes, including impaired spermatogenesis and cerebral ventriculomegaly. In both humans and mice, KATNAL2 is highly expressed in ciliated radial glia of the fetal ventricular-subventricular zone as well as in their postnatal ependymal and neuronal progeny. The ventriculomegaly observed in Katnal2 Δ17 mice is associated with disrupted primary cilia and ependymal planar cell polarity that results in impaired cilia-generated CSF flow. Further, prefrontal pyramidal neurons in ventriculomegalic Katnal2 Δ 17 mice exhibit decreased excitatory drive and reduced high-frequency firing. Consistent with these findings in mice, we identified rare, damaging heterozygous germline variants in KATNAL2 in five unrelated patients with neurosurgically treated CH and comorbid ASD or other neurodevelopmental disorders. Mice engineered with the orthologous ASD-associated KATNAL2 F244L missense variant recapitulated the ventriculomegaly found in human patients. Together, these data suggest KATNAL2 pathogenic variants alter intraventricular CSF homeostasis and parenchymal neuronal connectivity by disrupting microtubule dynamics in fetal radial glia and their postnatal ependymal and neuronal descendants. The results identify a molecular mechanism underlying the development of ventriculomegaly in a genetic subset of patients with ASD and may explain persistence of neurodevelopmental phenotypes in some patients with CH despite neurosurgical CSF shunting., Competing Interests: Competing interests statement:The authors declare no competing interest.

Hydrocephalus, characterized by cerebral ventriculomegaly, is the most common disorder requiring brain surgery in children. Recent studies have implicated SMARCC1, a component of the BRG1-associated factor (BAF) chromatin remodelling complex, as a candidate congenital hydrocephalus gene. However, SMARCC1 variants have not been systematically examined in a large patient cohort or conclusively linked with a human syndrome. Moreover, congenital hydrocephalus-associated SMARCC1 variants have not been functionally validated or mechanistically studied in vivo. Here, we aimed to assess the prevalence of SMARCC1 variants in an expanded patient cohort, describe associated clinical and radiographic phenotypes, and assess the impact of Smarcc1 depletion in a novel Xenopus tropicalis model of congenital hydrocephalus. To do this, we performed a genetic association study using whole-exome sequencing from a cohort consisting of 2697 total ventriculomegalic trios, including patients with neurosurgically-treated congenital hydrocephalus, that total 8091 exomes collected over 7 years (2016-23). A comparison control cohort consisted of 1798 exomes from unaffected siblings of patients with autism spectrum disorder and their unaffected parents were sourced from the Simons Simplex Collection. Enrichment and impact on protein structure were assessed in identified variants. Effects on the human fetal brain transcriptome were examined with RNA-sequencing and Smarcc1 knockdowns were generated in Xenopus and studied using optical coherence tomography imaging, in situ hybridization and immunofluorescence. SMARCC1 surpassed genome-wide significance thresholds, yielding six rare, protein-altering de novo variants localized to highly conserved residues in key functional domains. Patients exhibited hydrocephalus with aqueductal stenosis; corpus callosum abnormalities, developmental delay, and cardiac defects were also common. Xenopus knockdowns recapitulated both aqueductal stenosis and cardiac defects and were rescued by wild-type but not patient-specific variant SMARCC1. Hydrocephalic SMARCC1-variant human fetal brain and Smarcc1-variant Xenopus brain exhibited a similarly altered expression of key genes linked to midgestational neurogenesis, including the transcription factors NEUROD2 and MAB21L2. These results suggest de novo variants in SMARCC1 cause a novel human BAFopathy we term 'SMARCC1-associated developmental dysgenesis syndrome', characterized by variable presence of cerebral ventriculomegaly, aqueductal stenosis, developmental delay and a variety of structural brain or cardiac defects. These data underscore the importance of SMARCC1 and the BAF chromatin remodelling complex for human brain morphogenesis and provide evidence for a 'neural stem cell' paradigm of congenital hydrocephalus pathogenesis. These results highlight utility of trio-based whole-exome sequencing for identifying pathogenic variants in sporadic congenital structural brain disorders and suggest whole-exome sequencing may be a valuable adjunct in clinical management of congenital hydrocephalus patients., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Pathogenic protein-truncating variants of RAD51C, which plays an integral role in promoting DNA damage repair, increase the risk of breast and ovarian cancer. A large number of RAD51C missense variants of uncertain significance (VUS) have been identified, but the effects of the majority of these variants on RAD51C function and cancer predisposition have not been established. Here, analysis of 173 missense variants by a homology-directed repair (HDR) assay in reconstituted RAD51C-/- cells identified 30 nonfunctional (deleterious) variants, including 18 in a hotspot within the ATP-binding region. The deleterious variants conferred sensitivity to cisplatin and olaparib and disrupted formation of RAD51C/XRCC3 and RAD51B/RAD51C/RAD51D/XRCC2 complexes. Computational analysis indicated the deleterious variant effects were consistent with structural effects on ATP-binding to RAD51C. A subset of the variants displayed similar effects on RAD51C activity in reconstituted human RAD51C-depleted cancer cells. Case-control association studies of deleterious variants in women with breast and ovarian cancer and noncancer controls showed associations with moderate breast cancer risk [OR, 3.92; 95% confidence interval (95% CI), 2.18-7.59] and high ovarian cancer risk (OR, 14.8; 95% CI, 7.71-30.36), similar to protein-truncating variants. This functional data supports the clinical classification of inactivating RAD51C missense variants as pathogenic or likely pathogenic, which may improve the clinical management of variant carriers., Significance: Functional analysis of the impact of a large number of missense variants on RAD51C function provides insight into RAD51C activity and information for classification of the cancer relevance of RAD51C variants., (©2023 The Authors; Published by the American Association for Cancer Research.)

Objective: Autism, schizophrenia, and other clinically distinct neurodevelopmental psychiatric disorders (NPDs) have shared genetic etiologies, including single-gene and multigenic copy number variants (CNVs). Because rare variants are primarily investigated in clinical cohorts, population-based estimates of their prevalence and penetrance are lacking. The authors determined the prevalence, penetrance, and NPD risk of pathogenic single-gene variants in a large health care system population., Methods: The authors analyzed linked genomic and electronic health record (EHR) data in a subset of 90,595 participants from Geisinger's MyCode Community Health Initiative, known as the DiscovEHR cohort. Loss-of-function pathogenic variants in 94 high-confidence NPD genes were identified through exome sequencing, and NPD penetrance was calculated using preselected EHR diagnosis codes. NPD risk was estimated using a case-control comparison of DiscovEHR participants with and without NPD diagnoses. Results from single-gene variant analyses were also compared with those from 31 previously reported pathogenic NPD CNVs., Results: Pathogenic variants were identified in 0.34% of the DiscovEHR cohort and demonstrated a 34.3% penetrance for NPDs. Similar to CNVs, sequence variants collectively conferred a substantial risk for several NPD diagnoses, including autism, schizophrenia, and bipolar disorder. Significant NPD risk remained after participants with intellectual disability were excluded from the analysis, confirming the association with major psychiatric disorders in individuals without severe cognitive deficits., Conclusions: Collectively, rare single-gene variants and CNVs were found in >1% of individuals in a large health care system population and play an important contributory role in mental health disorders. Diagnostic genetic testing for pathogenic variants among symptomatic individuals with NPDs could improve clinical outcomes through early intervention and anticipatory therapeutic support.

Purpose: Neurodevelopmental disorders (NDDs), such as intellectual disability (ID) and autism spectrum disorder (ASD), exhibit genetic and phenotypic heterogeneity, making them difficult to differentiate without a molecular diagnosis. The Clinical Genome Resource Intellectual Disability/Autism Gene Curation Expert Panel (GCEP) uses systematic curation to distinguish ID/ASD genes that are appropriate for clinical testing (ie, with substantial evidence supporting their relationship to disease) from those that are not., Methods: Using the Clinical Genome Resource gene-disease validity curation framework, the ID/Autism GCEP classified genes frequently included on clinical ID/ASD testing panels as Definitive, Strong, Moderate, Limited, Disputed, Refuted, or No Known Disease Relationship., Results: As of September 2021, 156 gene-disease pairs have been evaluated. Although most (75%) were determined to have definitive roles in NDDs, 22 (14%) genes evaluated had either Limited or Disputed evidence. Such genes are currently not recommended for use in clinical testing owing to the limited ability to assess the effect of identified variants., Conclusion: Our understanding of gene-disease relationships evolves over time; new relationships are discovered and previously-held conclusions may be questioned. Without periodic re-examination, inaccurate gene-disease claims may be perpetuated. The ID/Autism GCEP will continue to evaluate these claims to improve diagnosis and clinical care for NDDs., Competing Interests: Conflict of Interest A.Br. is a shareholder of and employed by Natera. A.Br. has also been an employee of Invitae and Quest Diagnostics commercial laboratories. A.R.C. and K.B. are shareholders of and employed by Illumina, Inc. A.Be. is a shareholder of and is employed by Invitae. B.B. has received research support from Biomarin Pharmaceuticals Inc. He is currently employed by and is a shareholder of Alnylam Pharmaceuticals, Inc. All other authors declare no conflicts of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Purpose: Penetrance estimates of Birt-Hogg-Dubé syndrome (BHD)-associated cutaneous, pulmonary, and kidney manifestations are based on clinically ascertained families. In a health care system population, we used a genetics-first approach to estimate the prevalence of pathogenic/likely pathogenic (P/LP) truncating variants in FLCN, which cause BHD, and the penetrance of BHD-related phenotypes., Methods: Exomes from 135,990 patient-participants in Geisinger's MyCode cohort were assessed for P/LP truncating FLCN variants. BHD-related phenotypes were evaluated from electronic health records. Association between P/LP FLCN variants and BHD-related phenotypes was assessed using Firth's logistic regression., Results: P/LP truncating FLCN variants were identified in 35 individuals (1 in 3234 unrelated individuals), 68.6% of whom had BHD-related phenotype(s), including cystic lung disease (65.7%), pneumothoraces (17.1%), cutaneous manifestations (8.6%), and kidney cancer (2.9%). A total of 4 (11.4%) individuals had prior clinical BHD diagnoses., Conclusion: In this health care population, the frequency of P/LP truncating FLCN variants is 60 times higher than the previously reported prevalence. Although most variant-positive individuals had BHD-related phenotypes, a minority were previously clinically diagnosed, likely because cutaneous manifestations, pneumothoraces, and kidney cancer were observed at lower frequencies than in clinical cohorts. Improved clinical recognition of cystic lung disease and education concerning its association with FLCN variants could prompt evaluation for BHD., Competing Interests: Conflict of Interest D.H.L is an employee of Unified Patient Network, Inc and scientific consultant for Natera, Inc; MyOme, Inc; and Seven Bridges Genomics. All other authors declare no conflicts of interest., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The cyclin-dependent kinase inhibitor p27 (Kip1) is an important regulator of the G1/S checkpoint. It is degraded by the SCF-SKP2 complex in late G1 thereby allowing cells to progress to the S phase. Here we investigated the role of the E3 ubiquitin ligase RNF6 (Ring Finger Protein 6) in cell cycle progression in prostate cancer cells. Our data demonstrate that RNF6 can promote cell cycle progression by reducing the levels of p27. Knockdown of RNF6 led to an increase in the stability of p27 and to the arrest of cells in the G1 phase. RNF6 interacted with p27 via its KIL domain and this interaction was found to be phosphorylation independent. RNF6 enhanced ubiquitination and subsequent degradation of p27 in the early G0/G1 phase of the cell cycle. Knockdown of RNF6 expression by short hairpin RNA led to inhibition of the CDK2/Cyclin E complex thereby reducing phosphorylation of Retinoblastoma protein (Rb) and to a subsequent decrease in cell cycle progression and proliferation. Our data suggest that RNF6 acts as a negative regulator for p27 kip1 leading to its proteasome-dependent degradation in the early G0/G1 phase of the cell cycle.

BRCA2 is essential for homologous recombination DNA repair. BRCA2 mutations lead to genome instability and increased risk of breast and ovarian cancer. Similarly, mutations in BRCA2-interacting proteins are also known to modulate sensitivity to DNA damage agents and are established cancer risk factors. Here we identify the tumor suppressor CDK5RAP3 as a novel BRCA2 helical domain-interacting protein. CDK5RAP3 depletion induced DNA damage resistance, homologous recombination and single-strand annealing upregulation, and reduced spontaneous and DNA damage-induced genomic instability, suggesting that CDK5RAP3 negatively regulates double-strand break repair in the S-phase. Consistent with this cellular phenotype, analysis of transcriptomic data revealed an association between low CDK5RAP3 tumor expression and poor survival of breast cancer patients. Finally, we identified common genetic variations in the CDK5RAP3 locus as potentially associated with breast and ovarian cancer risk in BRCA1 and BRCA2 mutation carriers. Our results uncover CDK5RAP3 as a critical player in DNA repair and breast cancer outcomes.

To evaluate the racial and ethnic differences in prevalence of germline pathogenic variants (PVs) and the effect of race and ethnicity on breast cancer (BC) risk among carriers, results of multigene testing of 77 900 women with BC (non-Hispanic White [NHW] = 57 003; Ashkenazi-Jewish = 4798; Black = 6722; Hispanic = 5194; and Asian = 4183) were analyzed, and the frequency of PVs in each gene were compared between BC patients (cases) and race- and ethnicity-matched gnomAD reference controls. Compared with NHWs, BRCA1 PVs were enriched in Ashkenazi-Jews and Hispanics, whereas CHEK2 PVs were statistically significantly lower in Blacks, Hispanics, and Asians (all 2-sided P < .05). In case-control studies, BARD1 PVs were associated with high risks (odds ratio > 4.00) of BC in Blacks, Hispanics, and Asians; ATM PVs were associated with increased risk of BC among all races and ethnicities except Asians, whereas CHEK2 and BRIP1 PVs were associated with increased risk of BC among NHWs and Hispanics only. These findings suggest a need for personalized management of BC risk in PV carriers based on race and ethnicity., (© The Author(s) 2020. Published by Oxford University Press.)

Background: The germline cancer predisposition genes associated with increased risk of each clinical subtype of breast cancer, defined by estrogen receptor (ER), progesterone receptor (PR), and HER2, are not well defined., Methods: A total of 54 555 invasive breast cancer patients with 56 480 breast tumors were subjected to clinical hereditary cancer multigene panel testing. Heterogeneity for predisposition genes across clinical breast cancer subtypes was assessed by comparing mutation frequencies by gene among tumor subtypes and by association studies between each tumor subtype and reference controls., Results: Mutations in 15 cancer predisposition genes were detected in 8.6% of patients with ER+/HER2-; 8.9% with ER+/HER2+; 7.7% with ER-/HER2+; and 14.4% of ER-/PR-/HER2- tumors. BRCA1, BRCA2, BARD1, and PALB2 mutations were enriched in ER- and HER2- tumors; RAD51C and RAD51D mutations were enriched in ER- tumors only; TP53 mutations were enriched in HER2+ tumors, and ATM and CHEK2 mutations were enriched in both ER+ and/or HER2+ tumors. All genes were associated with moderate (odds ratio > 2.00) or strong (odds ratio > 5.00) risks of at least one subtype of breast cancer in case-control analyses. Mutations in ATM, BARD1, BRCA1, BRCA2, CHEK2, PALB2, RAD51C, RAD51D, and TP53 had predicted lifetime absolute risks of at least 20.0% for breast cancer., Conclusions: Germline mutations in hereditary cancer panel genes confer subtype-specific risks of breast cancer. Combined tumor subtype, age at breast cancer diagnosis, and family history of breast and/or ovarian cancer information provides refined categorical estimates of mutation prevalence for women considering genetic testing., (© The Author(s) 2020. Published by Oxford University Press.)

Purpose: Genetic testing of individuals often results in identification of genomic variants of unknown significance (VUS). Multiple lines of evidence are used to help determine the clinical significance of these variants., Methods: We analyzed ~138,000 individuals tested by multigene panel testing (MGPT). We used logistic regression to predict carrier status based on personal and family history of cancer. This was applied to 4644 tested individuals carrying 2383 BRCA1/2 variants to calculate likelihood ratios informing pathogenicity for each. Heterogeneity tests were performed for specific classes of variants defined by in silico predictions., Results: Twenty-two variants labeled as VUS had odds of >10:1 in favor of pathogenicity. The heterogeneity analysis found that among variants in functional domains that were predicted to be benign by in silico tools, a significantly higher proportion of variants were estimated to be pathogenic than previously indicated; that missense variants outside of functional domains should be considered benign; and that variants predicted to create de novo donor sites were also largely benign., Conclusion: The evidence presented here supports the use of personal and family history from MGPT in the classification of VUS and will be integrated into ongoing efforts to provide large-scale multifactorial classification.

Purpose: Several genes on hereditary breast and ovarian cancer susceptibility test panels have not been systematically examined for strength of association with disease. We employed the Clinical Genome Resource (ClinGen) clinical validity framework to assess the strength of evidence between selected genes and breast or ovarian cancer., Methods: Thirty-one genes offered on cancer panel testing were selected for evaluation. The strength of gene-disease relationship was systematically evaluated and a clinical validity classification of either Definitive, Strong, Moderate, Limited, Refuted, Disputed, or No Reported Evidence was assigned., Results: Definitive clinical validity classifications were made for 10/31 and 10/32 gene-disease pairs for breast and ovarian cancer respectively. Two genes had a Moderate classification whereas, 6/31 and 6/32 genes had Limited classifications for breast and ovarian cancer respectively. Contradictory evidence resulted in Disputed or Refuted assertions for 9/31 genes for breast and 4/32 genes for ovarian cancer. No Reported Evidence of disease association was asserted for 5/31 genes for breast and 11/32 for ovarian cancer., Conclusion: Evaluation of gene-disease association using the ClinGen clinical validity framework revealed a wide range of classifications. This information should aid laboratories in tailoring appropriate gene panels and assist health-care providers in interpreting results from panel testing.

Background: Increased risk of malignancies other than pancreatic cancer (PC) has been reported among first-degree relatives (FDRs) of PC patients; however, the roles of susceptibility gene mutations are unclear. We assessed risk for 15 cancers among FDRs of unselected PC probands., Methods: Data on 17 162 FDRs, with more than 336 000 person-years at risk, identified through 2305 sequential PC probands enrolled at Mayo Clinic (2000-2016) were analyzed. Family history data were provided by the probands. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated, comparing malignancies observed among the FDRs with that expected using Surveillance, Epidemiology, and End Results (SEER) data. Genetic testing was performed among a subset of probands (n = 2094), enabling stratified analyses among FDRs based on whether the related proband tested positive or negative for inherited mutation in 22 sequenced cancer susceptibility genes. All statistical tests were two-sided., Results: Compared with SEER, PC risk was twofold higher among FDRs of PC probands (SIR = 2.04, 95% CI = 1.78 to 2.31, P < .001). Primary liver cancer risk was elevated among female FDRs (SIR = 2.10, 95% CI = 1.34 to 3.12, P < .001). PC risk was more elevated among FDRs of mutation-positive probands (SIR = 4.32, 95% CI = 3.10 to 5.86) than FDRs of mutation-negative probands (SIR = 1.77, 95% CI = 1.51 to 2.05, between-group P < .001). FDR PC risk was higher when the related proband was younger than age 60 years at diagnosis and mutation-positive (SIR = 5.24, 95% CI = 2.93 to 8.64) than when the proband was younger than age 60 years but mutation-negative (SIR = 1.76, 95% CI = 1.21 to 2.47, between-group P < .001). Breast (SIR = 1.29, 95% CI = 1.01 to 1.63) and ovarian (SIR = 2.38, 95% CI = 1.30 to 4.00) cancers were elevated among FDRs of mutation-positive probands., Conclusions: Our study substantiates twofold risk of PC among FDRs of PC patients and suggests increased risk for primary liver cancer among female FDRs. FDRs of susceptibility mutation carriers had substantially increased risk for PC and increased risk for breast and ovarian cancers., (© The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: To improve methods for predicting the impact of missense variants of uncertain significance (VUS) in BRCA1 and BRCA2 on protein function., Methods: Functional data for 248 BRCA1 and 207 BRCA2 variants from assays with established high sensitivity and specificity for damaging variants were used to recalibrate 40 in silico algorithms predicting the impact of variants on protein activity. Additional random forest (RF) and naïve voting method (NVM) metapredictors for both BRCA1 and BRCA2 were developed to increase predictive accuracy., Results: Optimized thresholds for in silico prediction models significantly improved the accuracy of predicted functional effects for BRCA1 and BRCA2 variants. In addition, new BRCA1-RF and BRCA2-RF metapredictors showed area under the curve (AUC) values of 0.92 (95% confidence interval [CI]: 0.88-0.96) and 0.90 (95% CI: 0.84-0.95), respectively. Similarly, the BRCA1-NVM and BRCA2-NVM models had AUCs of 0.93 and 0.90. The RF and NVM models were used to predict the pathogenicity of all possible missense variants in BRCA1 and BRCA2., Conclusion: The recalibrated algorithms and new metapredictors significantly improved upon current models for predicting the impact of variants in cancer risk-associated domains of BRCA1 and BRCA2. Prediction of the functional impact of all possible variants in BRCA1 and BRCA2 provides important information about the clinical relevance of variants in these genes.

Purpose BRCA1/2 mutations are frequent in patients with triple-negative breast cancer (TNBC). These patients are often treated with primary systemic chemotherapy. The aim of this study was to analyze the effects of BRCA1/2 mutations on pathologic complete response (pCR) and disease-free survival (DFS) in a cohort of patients with TNBC treated with anthracycline and taxane-containing chemotherapy, with or without bevacizumab. Patients and Methods Germline DNA was sequenced to identify mutations in BRCA1 and BRCA2 in 493 patients with TNBC from the GeparQuinto study. The pCR rates were compared in patients with and without mutation, as well as in patients treated with and without bevacizumab. In addition, the influence of BRCA1/2 mutation status and pCR status on DFS was evaluated relative to treatment. Results BRCA1/2 mutations were detected in 18.3% of patients with TNBC. Overall, patients with mutations had a pCR rate of 50%, compared with 31.5% in patients without a mutation (odds ratio [OR], 2.17; 95% CI, 1.37 to 3.46; P = .001). The pCR rate among patients treated with bevacizumab was 61.5% for BRCA1/2 mutation carriers and 35.6% for those without mutations (OR, 2.90; 95% CI, 1.43 to 5.89; P = .004). pCR was a strong predictor of DFS for patients without BRCA1/2 mutations (hazard ratio, 0.18; 95% CI, 0.11 to 0.31) but not for patients with BRCA1/2 mutations (hazard ratio, 0.74; 95% CI, 0.32 to 1.69). Conclusion The addition of bevacizumab may increase the pCR after standard neoadjuvant chemotherapy for patients with TNBC with BRCA1/2 mutations. In patients treated with anthracycline and taxane-based chemotherapy (with or without bevacizumab), pCR was a weaker predictor of DFS for BRCA1/2 mutation carriers than for patients without mutations.

Background: Germline genetic testing with hereditary cancer gene panels can identify women at increased risk of breast cancer. However, those at increased risk of triple-negative (estrogen receptor-negative, progesterone receptor-negative, human epidermal growth factor receptor-negative) breast cancer (TNBC) cannot be identified because predisposition genes for TNBC, other than BRCA1, have not been established. The aim of this study was to define the cancer panel genes associated with increased risk of TNBC., Methods: Multigene panel testing for 21 genes in 8753 TNBC patients was performed by a clinical testing laboratory, and testing for 17 genes in 2148 patients was conducted by a Triple Negative Breast Cancer Consortium (TNBCC) of research studies. Associations between deleterious mutations in cancer predisposition genes and TNBC were evaluated using results from TNBC patients and reference controls., Results: Germline pathogenic variants in BARD1, BRCA1, BRCA2, PALB2, and RAD51D were associated with high risk (odds ratio > 5.0) of TNBC and greater than 20% lifetime risk for overall breast cancer among Caucasians. Pathogenic variants in BRIP1, RAD51C, and TP53 were associated with moderate risk (odds ratio > 2) of TNBC. Similar trends were observed for the African American population. Pathogenic variants in these TNBC genes were detected in 12.0% (3.7% non-BRCA1/2) of all participants., Conclusions: Multigene hereditary cancer panel testing can identify women with elevated risk of TNBC due to mutations in BARD1, BRCA1, BRCA2, PALB2, and RAD51D. These women can potentially benefit from improved screening, risk management, and cancer prevention strategies. Patients with mutations may also benefit from specific targeted therapeutic strategies., (© The Author(s) 2018. Published by Oxford University Press.)

Importance: Individuals genetically predisposed to pancreatic cancer may benefit from early detection. Genes that predispose to pancreatic cancer and the risks of pancreatic cancer associated with mutations in these genes are not well defined., Objective: To determine whether inherited germline mutations in cancer predisposition genes are associated with increased risks of pancreatic cancer., Design, Setting, and Participants: Case-control analysis to identify pancreatic cancer predisposition genes; longitudinal analysis of patients with pancreatic cancer for prognosis. The study included 3030 adults diagnosed as having pancreatic cancer and enrolled in a Mayo Clinic registry between October 12, 2000, and March 31, 2016, with last follow-up on June 22, 2017. Reference controls were 123 136 individuals with exome sequence data in the public Genome Aggregation Database and 53 105 in the Exome Aggregation Consortium database., Exposures: Individuals were classified based on carrying a deleterious mutation in cancer predisposition genes and having a personal or family history of cancer., Main Outcomes and Measures: Germline mutations in coding regions of 21 cancer predisposition genes were identified by sequencing of products from a custom multiplex polymerase chain reaction-based panel; associations of genes with pancreatic cancer were assessed by comparing frequency of mutations in genes of pancreatic cancer patients with those of reference controls., Results: Comparing 3030 case patients with pancreatic cancer (43.2% female; 95.6% non-Hispanic white; mean age at diagnosis, 65.3 [SD, 10.7] years) with reference controls, significant associations were observed between pancreatic cancer and mutations in CDKN2A (0.3% of cases and 0.02% of controls; odds ratio [OR], 12.33; 95% CI, 5.43-25.61); TP53 (0.2% of cases and 0.02% of controls; OR, 6.70; 95% CI, 2.52-14.95); MLH1 (0.13% of cases and 0.02% of controls; OR, 6.66; 95% CI, 1.94-17.53); BRCA2 (1.9% of cases and 0.3% of controls; OR, 6.20; 95% CI, 4.62-8.17); ATM (2.3% of cases and 0.37% of controls; OR, 5.71; 95% CI, 4.38-7.33); and BRCA1 (0.6% of cases and 0.2% of controls; OR, 2.58; 95% CI, 1.54-4.05)., Conclusions and Relevance: In this case-control study, mutations in 6 genes associated with pancreatic cancer were found in 5.5% of all pancreatic cancer patients, including 7.9% of patients with a family history of pancreatic cancer and 5.2% of patients without a family history of pancreatic cancer. Further research is needed for replication in other populations.

Many variants of uncertain significance (VUS) have been identified in BRCA2 through clinical genetic testing. VUS pose a significant clinical challenge because the contribution of these variants to cancer risk has not been determined. We conducted a comprehensive assessment of VUS in the BRCA2 C-terminal DNA binding domain (DBD) by using a validated functional assay of BRCA2 homologous recombination (HR) DNA-repair activity and defined a classifier of variant pathogenicity. Among 139 variants evaluated, 54 had ?99% probability of pathogenicity, and 73 had ?95% probability of neutrality. Functional assay results were compared with predictions of variant pathogenicity from the Align-GVGD protein-sequence-based prediction algorithm, which has been used for variant classification. Relative to the HR assay, Align-GVGD significantly (p < 0.05) over-predicted pathogenic variants. We subsequently combined functional and Align-GVGD prediction results in a Bayesian hierarchical model (VarCall) to estimate the overall probability of pathogenicity for each VUS. In addition, to predict the effects of all other BRCA2 DBD variants and to prioritize variants for functional studies, we used the endoPhenotype-Optimized Sequence Ensemble (ePOSE) algorithm to train classifiers for BRCA2 variants by using data from the HR functional assay. Together, the results show that systematic functional assays in combination with in silico predictors of pathogenicity provide robust tools for clinical annotation of BRCA2 VUS., (Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Purpose: The relevance of inherited pathogenic mutations in cancer predisposition genes in pancreatic cancer is not well understood. We aimed to assess the characteristics of patients with pancreatic cancer referred for hereditary cancer genetic testing and to estimate the risk of pancreatic cancer associated with mutations in panel-based cancer predisposition genes in this high-risk population., Methods: Patients with pancreatic cancer (N = 1,652) were identified from a 140,000-patient cohort undergoing multigene panel testing of predisposition genes between March 2012 and June 2016. Gene-level mutation frequencies relative to Exome Aggregation Consortium and Genome Aggregation Database reference controls were assessed., Results: The frequency of germline cancer predisposition gene mutations among patients with pancreatic cancer was 20.73%. Mutations in ATM, BRCA2, CDKN2A, MSH2, MSH6, PALB2, and TP53 were associated with high pancreatic cancer risk (odds ratio, > 5), and mutations in BRCA1 were associated with moderate risk (odds ratio, > 2). In a logistic regression model adjusted for age at diagnosis and family history of cancer, ATM and BRCA2 mutations were associated with personal history of breast or pancreatic cancer, whereas PALB2 mutations were associated with family history of breast or pancreatic cancer., Conclusion: These findings provide insight into the spectrum of mutations expected in patients with pancreatic cancer referred for cancer predisposition testing. Mutations in eight genes confer high or moderate risk of pancreatic cancer and may prove useful for risk assessment for pancreatic and other cancers. Family and personal histories of breast cancer are strong predictors of germline mutations., Competing Interests: AUTHORS’ DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The following represents disclosure information provided by authors of this manuscript. All relationships are considered compensated. Relationships are self-held unless noted. I = Immediate Family Member, Inst = My Institution. Relationships may not relate to the subject matter of this manuscript. For more information about ASCO’s conflict of interest policy, please refer to www.asco.org/rwcorascopubs.org/po/author-center. Chunling Hu No relationship to disclose Holly LaDuca Employment: Ambry Genetics Stock and Other Ownership Interests: Ambry Genetics Hermela Shimelis No relationship to disclose Eric C. Polley Research Funding: GRAIL Jenna Lilyquist No relationship to disclose Steven N. Hart No relationship to disclose Jie Na No relationship to disclose Abigail Thomas No relationship to disclose Kun y. Lee No relationship to disclose Brigette Tippin Davis Employment: Ambry Genetics Stock and Other Ownership Interests: Ambry Genetics Research Funding: Ambry Genetics (Inst) Travel, Accommodations, Expenses: Ambry Genetics Mary Helen Black Employment: Ambry Genetics Research Funding: Ambry Genetics Travel, Accommodations, Expenses: Ambry Genetics Tina Pesaran Employment: Ambry Genetics Stock and Other Ownership Interests: Ambry Genetics Travel, Accommodations, Expenses: Ambry Genetics David E. Goldgar No relationship to disclose Jill S. Dolinsky Employment: Ambry Genetics Fergus J. Couch Consulting or Advisory Role: AstraZeneca Research Funding: GRAIL Other Relationship: Ambry Genetics

Most common breast cancer susceptibility variants have been identified through genome-wide association studies (GWAS) of predominantly estrogen receptor (ER)-positive disease. We conducted a GWAS using 21,468 ER-negative cases and 100,594 controls combined with 18,908 BRCA1 mutation carriers (9,414 with breast cancer), all of European origin. We identified independent associations at P < 5 × 10 -8 with ten variants at nine new loci. At P < 0.05, we replicated associations with 10 of 11 variants previously reported in ER-negative disease or BRCA1 mutation carrier GWAS and observed consistent associations with ER-negative disease for 105 susceptibility variants identified by other studies. These 125 variants explain approximately 16% of the familial risk of this breast cancer subtype. There was high genetic correlation (0.72) between risk of ER-negative breast cancer and breast cancer risk for BRCA1 mutation carriers. These findings may lead to improved risk prediction and inform further fine-mapping and functional work to better understand the biological basis of ER-negative breast cancer.

Objectives: Given the lack of adequate screening modalities, knowledge of ovarian cancer risks for carriers of pathogenic alterations in predisposition genes is important for decisions about risk-reduction by salpingo-oophorectomy. We sought to determine which genes assayed on multi-gene panels are associated with ovarian cancer, the magnitude of the associations, and for which clinically meaningful associations could be ruled out., Methods: 7768 adult ovarian cancer cases of European ancestry referred to a single clinical testing laboratory underwent multi-gene panel testing for detection of pathogenic alterations in known or suspected ovarian cancer susceptibility genes. A targeted capture approach was employed to assay each of 19 genes for the presence of pathogenic or likely pathogenic alterations. Mutation frequencies in ovarian cancer cases were compared to mutation frequencies in individuals from the Exome Aggregation Consortium (ExAC). Analyses stratified by family and personal history of other cancers and age at diagnosis were also performed., Results: Significant associations (p<0.001) were identified between alterations in 11 genes and ovarian cancer, with eight of these displaying ≥5-fold increased risk (BRCA1, BRCA2, BRIP1, MSH2, MSH6, RAD51C, RAD51D). Relative risks of ovarian cancer greater than two-fold were also observed for ATM, but could reliably be ruled out for RAD50 and CHEK2., Conclusions: These results will inform clinical management of women found to carry pathogenic alterations in genes tested on multi-gene panels. The knowledge that some genes are not associated with OC can reduce concerns of women found to carry pathogenic alterations in those genes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Importance: Germline pathogenic variants in BRCA1 and BRCA2 predispose to an increased lifetime risk of breast cancer. However, the relevance of germline variants in other genes from multigene hereditary cancer testing panels is not well defined., Objective: To determine the risks of breast cancer associated with germline variants in cancer predisposition genes., Design, Setting, and Participants: A study population of 65 057 patients with breast cancer receiving germline genetic testing of cancer predisposition genes with hereditary cancer multigene panels. Associations between pathogenic variants in non-BRCA1 and non-BRCA2 predisposition genes and breast cancer risk were estimated in a case-control analysis of patients with breast cancer and Exome Aggregation Consortium reference controls. The women underwent testing between March 15, 2012, and June 30, 2016., Main Outcomes and Measures: Breast cancer risk conferred by pathogenic variants in non-BRCA1 and non-BRCA2 predisposition genes., Results: The mean (SD) age at diagnosis for the 65 057 women included in the analysis was 48.5 (11.1) years. The frequency of pathogenic variants in 21 panel genes identified in 41 611 consecutively tested white women with breast cancer was estimated at 10.2%. After exclusion of BRCA1, BRCA2, and syndromic breast cancer genes (CDH1, PTEN, and TP53), observed pathogenic variants in 5 of 16 genes were associated with high or moderately increased risks of breast cancer: ATM (OR, 2.78; 95% CI, 2.22-3.62), BARD1 (OR, 2.16; 95% CI, 1.31-3.63), CHEK2 (OR, 1.48; 95% CI, 1.31-1.67), PALB2 (OR, 7.46; 95% CI, 5.12-11.19), and RAD51D (OR, 3.07; 95% CI, 1.21-7.88). Conversely, variants in the BRIP1 and RAD51C ovarian cancer risk genes; the MRE11A, RAD50, and NBN MRN complex genes; the MLH1 and PMS2 mismatch repair genes; and NF1 were not associated with increased risks of breast cancer., Conclusions and Relevance: This study establishes several panel genes as high- and moderate-risk breast cancer genes and provides estimates of breast cancer risk associated with pathogenic variants in these genes among individuals qualifying for clinical genetic testing.

Breast cancer risks conferred by many germline missense variants in the BRCA1 and BRCA2 genes, often referred to as variants of uncertain significance (VUS), have not been established. In this study, associations between 19 BRCA1 and 33 BRCA2 missense substitution variants and breast cancer risk were investigated through a breast cancer case-control study using genotyping data from 38 studies of predominantly European ancestry (41,890 cases and 41,607 controls) and nine studies of Asian ancestry (6,269 cases and 6,624 controls). The BRCA2 c.9104A>C, p.Tyr3035Ser (OR = 2.52; P = 0.04), and BRCA1 c.5096G>A, p.Arg1699Gln (OR = 4.29; P = 0.009) variant were associated with moderately increased risks of breast cancer among Europeans, whereas BRCA2 c.7522G>A, p.Gly2508Ser (OR = 2.68; P = 0.004), and c.8187G>T, p.Lys2729Asn (OR = 1.4; P = 0.004) were associated with moderate and low risks of breast cancer among Asians. Functional characterization of the BRCA2 variants using four quantitative assays showed reduced BRCA2 activity for p.Tyr3035Ser compared with wild-type. Overall, our results show how BRCA2 missense variants that influence protein function can confer clinically relevant, moderately increased risks of breast cancer, with potential implications for risk management guidelines in women with these specific variants. Cancer Res; 77(11); 2789-99. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Purpose: Genetic predisposition to male breast cancer (MBC) is not well understood. The aim of this study was to better define the predisposition genes contributing to MBC and the utility of germline multi-gene panel testing (MGPT) for explaining the etiology of MBCs., Methods: Clinical histories and molecular results were retrospectively reviewed for 715 MBC patients who underwent MGPT from March 2012 to June 2016., Results: The detection rate of MGPT was 18.1% for patients tested for variants in 16 breast cancer susceptibility genes and with no prior BRCA1/2 testing. BRCA2 and CHEK2 were the most frequently mutated genes (11.0 and 4.1% of patients with no prior BRCA1/2 testing, respectively). Pathogenic variants in BRCA2 [odds ratio (OR) = 13.9; p = 1.92 × 10 -16 ], CHEK2 (OR = 3.7; p = 6.24 × 10 -24 ), and PALB2 (OR = 6.6, p = 0.01) were associated with significantly increased risks of MBC. The average age at diagnosis of MBC was similar for patients with (64 years) and without (62 years) pathogenic variants. CHEK2 1100delC carriers had a significantly lower average age of diagnosis (n = 7; 54 years) than all others with pathogenic variants (p = 0.03). No significant differences were observed between history of additional primary cancers (non-breast) and family history of male breast cancer for patients with and without pathogenic variants. However, patients with pathogenic variants in BRCA2 were more likely to have a history of multiple primary breast cancers., Conclusion: These data suggest that all MBC patients regardless of age of diagnosis, history of multiple primary cancers, or family history of MBC should be offered MGPT., Competing Interests: Mary Pritzlaff, Pia Summerour, Shuwei Li, Patrick Reineke, Jill S. Dolinsky, Rachel McFarland, and Holly LaDuca are employees of Ambry Genetics. Jill S. Dolinsky and Elizabeth Chao are stock holders of Ambry Genetics. The other authors have nothing to disclose. Ethical Approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required. The research presented here complies with the current laws of the United States of America. Research involving human and animal rights This article does not contain any studies with animals performed by any of the authors.

Background: The K3326X variant in BRCA2 (BRCA2*c.9976A>T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers., Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided., Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10(-) (6)) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10(-3)). These associations were stronger for serous ovarian cancer and for estrogen receptor-negative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10(-5) and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10(-5), respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed., Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Inherited predisposition to breast cancer is known to be caused by loss-of-function mutations in BRCA1, BRCA2, PALB2, CHEK2, and other genes involved in DNA repair. However, most families severely affected by breast cancer do not harbor mutations in any of these genes. In Finland, founder mutations have been observed in each of these genes, suggesting that the Finnish population may be an excellent resource for the identification of other such genes. To this end, we carried out exome sequencing of constitutional genomic DNA from 24 breast cancer patients from 11 Finnish breast cancer families. From all rare damaging variants, 22 variants in 21 DNA repair genes were genotyped in 3,166 breast cancer patients, 569 ovarian cancer patients, and 2,090 controls, all from the Helsinki or Tampere regions of Finland. In Fanconi anemia complementation gene M (FANCM), nonsense mutation c.5101C>T (p.Q1701X) was significantly more frequent among breast cancer patients than among controls [odds ratio (OR) = 1.86, 95% CI = 1.26-2.75; P = 0.0018], with particular enrichment among patients with triple-negative breast cancer (TNBC; OR = 3.56, 95% CI = 1.81-6.98, P = 0.0002). In the Helsinki and Tampere regions, respectively, carrier frequencies of FANCM p.Q1701X were 2.9% and 4.0% of breast cancer patients, 5.6% and 6.6% of TNBC patients, 2.2% of ovarian cancer patients (from Helsinki), and 1.4% and 2.5% of controls. These findings identify FANCM as a breast cancer susceptibility gene, mutations in which confer a particularly strong predisposition for TNBC.

Androgen receptor (AR) plays a pivotal role in prostate cancer. Regulation of AR transcriptional activity by post-translational modifications, such as phosphorylation by multiple kinases, is well documented. Here, we report that two PIM-1 kinase isoforms which are up-regulated during prostate cancer progression, namely PIM-1S and PIM-1L, modulate AR stability and transcriptional activity through differentially phosphorylating AR at serine 213 (Ser-213) and threonine 850 (Thr-850). Although both kinases are capable of interacting with and phosphorylating AR at Ser-213, only PIM-1L could phosphorylate Thr-850. We also showed that PIM-1S induced Ser-213 phosphorylation destabilizes AR by recruiting the ubiquitin E3 ligase Mdm2 and promotes AR degradation in a cell cycle-dependent manner, while PIM-1L-induced Thr-850 phosphorylation stabilizes AR by recruiting the ubiquitin E3 ligase RNF6 and promotes AR-mediated transcription under low-androgen conditions. Furthermore, both PIM-1 isoforms could promote prostate cancer cell growth under low-androgen conditions. Our data suggest that these kinases regulate AR stability and transcriptional activity through recruitment of different functional partners in a phosphorylation-dependent manner. As AR turnover has been previously shown to be critical for cell cycle progression in prostate cancer cells, PIM-1 kinase isoforms may promote prostate cancer cell growth, at least in part, through modulating AR activity via distinct mechanisms.

Progression from the androgen-sensitive to androgen-insensitive (or castration-resistant) stage is the major obstacle for sustained effectiveness of hormonal therapy for prostate cancer. The androgen receptor (AR) and its splice variants play important roles in regulating the transcription program essential for castration resistance. Here, we report the identification of a novel AR splice variant, designated as AR8, which is up-regulated in castration-resistant prostate cancer cells. AR8 is structurally different from other known AR splice variants because it lacks a DNA binding domain and therefore, unlikely functions as a transcription factor on its own. Immunofluorescence staining revealed that AR8 was primarily localized on the plasma membrane, possibly through palmitoylation of two cysteine residues within its unique C-terminal sequence. Mutation of these putative palmitoylation sites in AR8 led to loss of its plasma membrane localization. In addition, we demonstrated that overexpression of AR8 in prostate cancer cells promoted association of Src and AR with the EGF receptor in response to EGF treatment and enhanced tyrosine phosphorylation of AR. Conversely, specific knockdown of AR8 expression in prostate cancer cells compromised EGF-induced Src activation and AR phosphorylation. This effect was accompanied with attenuation of proliferation and increased apoptosis in prostate cancer cells cultured in androgen-depleted medium. We also showed that AR8 was required for optimal transcriptional activity of AR in response to treatment of both androgen and EGF. Taken together, our results demonstrate that the membrane-associated AR8 isoform may contribute to castration resistance by potentiating AR-mediated proliferative and survival responses to hormones and growth factors.

The androgen receptor (AR) plays a critical role in prostate cancer. We have identified a ubiquitin E3 ligase, RNF6, as an AR-associated protein in a proteomic screen. RNF6 induces AR ubiquitination and promotes AR transcriptional activity. Specific knockdown of RNF6 or mutation of RNF6-induced ubiquitination acceptor sites on AR selectively alters expression of a subset of AR target genes and diminishes recruitment of AR and its coactivators to androgen-responsive elements present in the regulatory region of these genes. Furthermore, RNF6 is overexpressed in hormone-refractory human prostate cancer tissues and required for prostate cancer cell growth under androgen-depleted conditions. Our data suggest that RNF6-induced ubiquitination may regulate AR transcriptional activity and specificity through modulating cofactor recruitment.

We previously showed that the 44-kDa serine/threonine kinase Pim-1 (Pim-1L) can protect prostate cancer cells from apoptosis induced by chemotherapeutic drugs (Xie, Y., Xu, K., Dai, B., Guo, Z., Jiang, T., Chen, H., and Qiu, Y. (2006) Oncogene 25, 70-78). To further explore the mechanisms of Pim-1L-mediated resistance to chemotherapeutic drugs in prostate cancer cells, we employed a yeast two-hybrid screening to identify cellular proteins that were associated with Pim-1L, and we found the ABC transporter BCRP/ABCG2 as one of the potential interacting partners of Pim-1L. We also showed that the expression level of Pim-1L and BCRP was up-regulated in mitoxantrone and docetaxel-resistant prostate cancer cell lines. Pim-1L was co-localized with BCRP on the plasma membrane and induced phosphorylation of BCRP at threonine 362. Knocking-down Pim-1L expression in the drug-resistant prostate cancer cells abolished multimer formation of endogenous BCRP and resensitized the resistant cells to chemotherapeutic drugs suggesting that BCRP phosphorylation induced by Pim-1L was essential for its functionality. This is further corroborated by our finding that the plasma membrane localization and drug-resistant activity of BCRP were compromised by T362A mutation. Our data suggest that Pim-1L may protect prostate cancer cells from apoptosis, at least in part, through regulation of transmembrane drug efflux pump. These findings may provide a potential therapeutic approach by disrupting Pim-1 signaling to reverse BCRP-mediated multidrug resistance.