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Precision oncology is making remarkable advancements in optimizing patient care by personalizing treatments. To date, the US Food and Drug Administration (FDA) has approved poly(ADP-ribose) polymerase inhibitors (PARPi) olaparib (Lynparza, AstraZeneca and Merck) and talazoparib (Talzenna, Pfizer Oncology Together™) for germline or somatic BRCA1/2-mutated metastatic breast cancer (BC) patients, and PI3K inhibitor alpelisib (Piqray, Novartis) plus fulvestrant for patients with hormone receptor-positive human epidermal growth factor receptor 2-negative (HR+HER2-) PIK3CA-mutated advanced BC. In addition, the FDA approved capivasertib (Trucap, AstraZeneca) for HR+HER2- locally advanced or metastatic BC patients with one or more AKT1, PIK3CA, or PTEN alterations. Finally, the FDA recently approved elacestrant (Orserdu, Stemline Therapeutics, Inc.) for postmenopausal patients with ER+ HER2- ESR1-mutated advanced or metastatic BC with disease progression following at least one line of endocrine therapy. This study presents a single institutional retrospective review of genomic reports of patients with BC. Analysis of genomic reports of 1361 BC sequencing reports was performed for 1010 patients with BC from 2013 to 2023 (23% of patients had multiple reports). Eligible patients had at least one primary or metastatic tumor. Multiple sequencing platforms were used for FFPE specimens including Tempus xT targeted next-generation sequencing (NGS), Foundation One Medicine, HopeSeq, Ashion Analytics GEM ExTra, and Exact Sciences Oncomap. Liquid biopsies were performed by Guardant, Tempus, and Foundation One Medicine. Chart reviews were performed to collect patient characteristics. BRCA1/2-mutated, metastatic BC patients who initiated treatment with olaparib or talazoparib, and PIK3CA-mutated, HR+ metastatic BC patients who initiated treatment with alpelisib were reported. In addition, patients with ESR1 or AKT1/PIK3CA/PTEN mutations were identified. Clinical outcomes, including progression-free survival (PFS) and overall survival (OS) were analyzed for BRCA1/2 and PIK3CA-mutated patients who received PARPi or alpelisib. Survival curves were generated using the Kaplan Meier method. A cohort of 1010 BC patients with 1361 genomic reports was identified. A total of 935/1361 (69%) specimens were formalin-fixed paraffin-embedded (FFPE) tumor biopsies and 426/1361 (31%) were liquid biopsies. Receptor status included 65% HR+HER2-, 8% HR+HER2+, 4% HR-HER2+, and 23% TNBC. Racial and ethnic distribution of these patients included 50% non-Hispanic White, 26% Hispanic, 17% Asian, 6% African American, 1% other (Native Hawaiian or Other Pacific Islander, American Indian or Alaska Native, or unknown). Sequencing platforms included 30% Tempus xT, 31% Foundation One, 10% HopeSeq, 20% GEM ExTra, and 9% Exact Sciences. Liquid biopsies included 79% Guardant, 20% Tempus, and 1% Foundation One. Of 1010 patients, the most common mutations were TP53 (44%), PIK3CA (38%), ESR1 (14%), PTEN (12%), CCND1 (11%), FGFR1 (10%), CDH1 (10%), ERBB2 (9%), MYC (9%), FGF3 (8%), GATA3 (8%), FGF19 (8%), FGF4 (7%), ARID1A (6%), RB1 (5%), BRCA2 (5%), MAP3K1 (4%), AKT1 (4%), NF1 (4%), MLL3 (4%), ZNF703 (4%), CDKN2A (4%), BRCA1 (4%), MCL1 (3%), ATM (3%), PALB2 (1%), and CHEK2 (1%). The majority of reports with tumor mutation burden (TMB) results (97%) had low or intermediate TMB. A total of 784 actionable mutations in 1010 patients were reported, including 381/1010 (38%) PIK3CA; 144/1010 (14%) ESR1; 122/1010 (12%) PTEN; 48/1010 (5%) BRCA2; 36/1010 (4%) BRCA1; 41/1010 (4%) AKT1; and 12/1010 (1%) PALB2. Of the 96/1010 (10%) patients with BRCA1, BRCA2, or PALB2 mutations not including variants of uncertain significance (VUS), 33/96 (34.4%) received olaparib and 3/96 (3%) received talazoparib in the metastatic setting, and 28 were eligible for response (one had toxicity, two were lost to follow-up, and two went to hospice). Median PFS was 9.0 months and median OS was 21.8 months for patients receiving PARPi. Of the 381/1010 (38%) patients with PIK3CA mutations, 84/381 (22%) received alpelisib and 41 were eligible for response (22 had toxicity, 13 were discontinued, six were lost to follow-up, and two went to hospice). Median PFS was 7.9 months and median OS was 31.2 months for patients receiving alpelisib. A total of 544/1010 (54%) patients had AKT1, PIK3CA, or PTEN mutations which are now FDA approved for capivasertib in HR+HER2- metastatic BC patients. In addition, 144/1010 (14%) patients had ESR1 mutations which are FDA approved for elacestrant in HR+HER2- metastatic BC patients. In this study, a total of 784 clinically actionable mutations were reported for 1010 patients with genomic sequencing. Of these, 96/1010 (10%) patients had at least one actionable mutation in homologous recombination repair genes (BRCA1, BRCA2, PALB2) and 36/96 (37.5%) patients received PARP inhibitors (33 olaparib and three talazoparib). In addition, 381/1010 (38%) patients had at least one clinically actionable PIK3CA mutation, and 84/381 (22%) received alpelisib. Additionally, 544/1010 (54%) of patients had either AKT1 (41/1010), PIK3CA (381/1010), or PTEN (122/1010) alterations that were FDA approved in November 2023 for capivasertib in the treatment of HR+HER2- metastatic BC (MBC) patients. Furthermore, 144/1010 (14%) patients in this study had at least one ESR1 mutation, a clinically actionable mutation that was FDA approved in January 2023 for elacestrant in the treatment of ER+HER2- MBC patients (44% detected by liquid biopsy). Future studies are needed to determine the efficacy of elacestrant and capivasertib for patients with these mutations, and to tailor strategies for optimal patient quality of life and cancer outcome. Show less

Variants with large effect contribute to congenital heart disease (CHD). To date, recessive genotypes (RGs) have commonly been implicated through anecdotal ascertainment of consanguineous families and candidate gene-based analysis; the recessive contribution to the broad range of CHD phenotypes has been limited. We analyzed whole exome sequences of 5,424 CHD probands. Rare damaging RGs were estimated to contribute to at least 2.2% of CHD, with greater enrichment among laterality phenotypes (5.4%) versus other subsets (1.4%). Among 108 curated human recessive CHD genes, there were 66 RGs, with 54 in 11 genes with >1 RG, 12 genes with 1 RG, and 85 genes with zero. RGs were more prevalent among offspring of consanguineous union (4.7%, 32/675) than among nonconsanguineous probands (0.7%, 34/4749). Founder variants in Show less

Gene expression profiling of rare cancers has proven challenging due to limited access to patient materials and requirement of intact, non-degraded RNA for next-generation sequencing. We customized a gene expression panel compatible with degraded RNA from formalin-fixed, paraffin-embedded (FFPE) patient cancer samples and investigated its utility in pathway activity profiling in patients with metaplastic breast cancer (MpBC). Activity of various biological pathways was profiled in samples from nineteen patients with MpBC and 8 patients with invasive ductal carcinoma with triple negative breast cancer (TNBC) phenotype using a custom gene expression-based assay of 345 genes. MpBC samples of mesenchymal (chondroid and/or osteoid) histology demonstrated increased SNAI1 and BCL2L11 pathway activity compared to samples with non-mesenchymal histology. Additionally, late cornified envelope and keratinization genes were downregulated in MpBC compared to TNBC, and epithelial-to-mesenchymal transition (EMT) and collagen genes were upregulated in MpBC. Patients with high activity of an invasiveness gene expression signature, as well as high expression of the mesenchymal marker and extracellular matrix glycoprotein gene SPARC, experienced worse outcomes than those with low invasiveness activity and low SPARC expression. This study demonstrates the utility of gene expression profiling of metaplastic breast cancer FFPE samples with a custom counts-based assay. Gene expression patterns identified by this assay suggest that, although often histologically triple negative, patients with MpBC have distinct pathway activation compared to patients with invasive ductal TNBC. Incorporation of targeted therapies may lead to improved outcome for MpBC patients, especially in those patients expressing increased activity of invasiveness pathways. Show less

The vertebrate body plan features a consistent left-right (LR) asymmetry of internal organs. In several vertebrate embryos, motile cilia generate an asymmetric fluid flow that is necessary for normal LR development. However, the mechanisms involved in orienting LR asymmetric flow with previously established anteroposterior (AP) and dorsoventral (DV) axes remain poorly understood. In zebrafish, asymmetric flow is generated in Kupffer's vesicle (KV). The cellular architecture of KV is asymmetric along the AP axis, with more ciliated cells densely packed into the anterior region. Here, we identify a Rho kinase gene, rock2b, which is required for normal AP patterning of KV and subsequent LR development in the embryo. Antisense depletion of rock2b in the whole embryo or specifically in the KV cell lineage perturbed asymmetric gene expression in lateral plate mesoderm and disrupted organ LR asymmetries. Analyses of KV architecture demonstrated that rock2b knockdown altered the AP placement of ciliated cells without affecting cilia number or length. In control embryos, leftward flow across the anterior pole of KV was stronger than rightward flow at the posterior end, correlating with the normal AP asymmetric distribution of ciliated cells. By contrast, rock2b knockdown embryos with AP patterning defects in KV exhibited randomized flow direction and equal flow velocities in the anterior and posterior regions. Live imaging of Tg(dusp6:memGFP)(pt19) transgenic embryos that express GFP in KV cells revealed that rock2b regulates KV cell morphology. Our results suggest a link between AP patterning of the ciliated Kupffer's vesicle and LR patterning of the zebrafish embryo. Show less

The Wnt/beta-catenin signaling pathway is critical in both cellular proliferation and organismal development. However, how the beta-catenin degradation complex is inhibited upon Wnt activation remains unclear. Using a directed RNAi screen we find that protein phosphatase 1 (PP1), a ubiquitous serine/threonine phosphatase, is a novel potent positive physiologic regulator of the Wnt/beta-catenin signaling pathway. PP1 expression synergistically activates, and inhibition of PP1 inhibits, Wnt/beta-catenin signaling in Drosophila and mammalian cells as well as in Xenopus embryos. The data suggest that PP1 controls Wnt signaling through interaction with, and regulated dephosphorylation of, axin. Inhibition of PP1 leads to enhanced phosphorylation of specific sites on axin by casein kinase I. Axin phosphorylation markedly enhances the binding of glycogen synthase kinase 3, leading to a more active beta-catenin destruction complex. Wnt-regulated changes in axin phosphorylation, mediated by PP1, may therefore determine beta-catenin transcriptional activity. Specific inhibition of PP1 in this pathway may offer therapeutic approaches to disorders with increased beta-catenin signaling. Show less

Wnt signaling increases beta-catenin abundance and transcription of Wnt-responsive genes. Our previous work suggested that the B56 regulatory subunit of protein phosphatase 2A (PP2A) inhibits Wnt signaling. Okadaic acid (a phosphatase inhibitor) increases, while B56 expression reduces, beta-catenin abundance; B56 also reduces transcription of Wnt-responsive genes. Okadaic acid is a tumor promoter, and the structural A subunit of PP2A is mutated in multiple cancers. Taken together, the evidence suggests that PP2A is a tumor suppressor. However, other studies suggest that PP2A activates Wnt signaling. We now show that the B56, A and catalytic C subunits of PP2A each have ventralizing activity in Xenopus embryos. B56 was epistatically positioned downstream of GSK3beta and axin but upstream of beta-catenin, and axin co-immunoprecipitated B56, A and C subunits, suggesting that PP2A:B56 is in the beta-catenin degradation complex. PP2A appears to be essential for beta-catenin degradation, since beta-catenin degradation was reconstituted in phosphatase-depleted Xenopus egg extracts by PP2A, but not PP1. These results support the hypothesis that PP2A:B56 directly inhibits Wnt signaling and plays a role in development and carcinogenesis. Show less

Glycogen synthase kinase 3 (GSK-3) is a constitutively active kinase that negatively regulates its substrates, one of which is beta-catenin, a downstream effector of the Wnt signaling pathway that is required for dorsal-ventral axis specification in the Xenopus embryo. GSK-3 activity is regulated through the opposing activities of multiple proteins. Axin, GSK-3, and beta-catenin form a complex that promotes the GSK-3-mediated phosphorylation and subsequent degradation of beta-catenin. Adenomatous polyposis coli (APC) joins the complex and downregulates beta-catenin in mammalian cells, but its role in Xenopus is less clear. In contrast, GBP, which is required for axis formation in Xenopus, binds and inhibits GSK-3. We show here that GSK-3 binding protein (GBP) inhibits GSK-3, in part, by preventing Axin from binding GSK-3. Similarly, we present evidence that a dominant-negative GSK-3 mutant, which causes the same effects as GBP, keeps endogenous GSK-3 from binding to Axin. We show that GBP also functions by preventing the GSK-3-mediated phosphorylation of a protein substrate without eliminating its catalytic activity. Finally, we show that the previously demonstrated axis-inducing property of overexpressed APC is attributable to its ability to stabilize cytoplasmic beta-catenin levels, demonstrating that APC is impinging upon the canonical Wnt pathway in this model system. These results contribute to our growing understanding of how GSK-3 regulation in the early embryo leads to regional differences in beta-catenin levels and establishment of the dorsal axis. Show less