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There is an urgent need to identify biomarkers of early response that can accurately predict the benefit of immune checkpoint inhibitors (ICI). Patients receiving durvalumab/tremelimumab had tumor samples sequenced before treatment (baseline) to identify variants for the design of a personalized circulating tumor (ctDNA) assay. ctDNA was assessed at baseline and at 4 and/or 8 weeks into treatment. Correlations between ctDNA changes to radiographic response and overall survival (OS) were made to assess potential clinical benefit. 35/40 patients (87.5%) had personalized ctDNA assays designed, and 29/35 (82.9%) had plasma available for baseline analysis, representing 16 unique solid tumor histologies. As early as 4 weeks after treatment, decline in ctDNA from baseline predicted improved OS (P = 0.0144; HR = 9.98) and ctDNA changes on treatment‐supported and refined radiographic response calls. ctDNA clearance at any time through week 8 identified complete responders by a median lead time of 11.5 months ahead of radiographic imaging. ctDNA response monitoring is emerging as a dynamic, personalized biomarker method that may predict survival outcomes in patients with diverse solid tumor histologies, complementing and sometimes preceding standard‐of‐care imaging assessments. [ABSTRACT FROM AUTHOR]

Wnt signaling increases bone mass by stimulating osteoblast lineage commitment and expansion and forms the basis for novel anabolic therapeutic strategies being developed for osteoporosis. These strategies include derepression of Wnt signaling by targeting secreted Wnt pathway antagonists, such as sclerostin. However, such therapies are associated with safety concerns regarding an increased risk of osteosarcoma, the most common primary malignancy of bone. Here, we analyzed 5 human osteosarcoma cell lines in a high-throughput screen for epigenetically silenced tumor suppressor genes and identified Wnt inhibitory factor 1 (WIF1), which encodes an endogenous secreted Wnt pathway antagonist, as a candidate tumor suppressor gene. In vitro, WIF1 suppressed [beta]-catenin levels in human osteosarcoma cell lines, induced differentiation of human and mouse primary osteoblasts, and suppressed the growth of mouse and human osteosarcoma cell lines. Wif1 was highly expressed in the developing and mature mouse skeleton, and, although it was dispensable for normal development, targeted deletion of mouse Wif1 accelerated development of radiation-induced osteosarcomas in vivo. In primary human osteosarcomas, silencing of WIF1 by promoter hypermethylation was associated with loss of differentiation, increased [beta]-catenin levels, and increased proliferation. These data lead us to suggest that derepression of Wnt signaling by targeting secreted Wnt antagonists in osteoblasts may increase susceptibility to osteosarcoma., Introduction Osteosarcoma is the most common primary malignancy of bone, and the third most common cancer in adolescents (1). Risk factors for osteosarcoma include states associated with increased osteoblast proliferation, [...]

Genomic amplification of 19q12 occurs in several cancer types including ovarian cancer where it is associated with primary treatment failure. We systematically attenuated expression of genes within the minimally defined 19q12 region in ovarian cell lines using short-interfering RNAs (siRNA) to identify driver oncogene(s) within the amplicon. Knockdown of CCNE1 resulted in G1/S phase arrest, reduced cell viability and apoptosis only in amplification-carrying cells. Although CCNE1 knockdown increased cisplatin resistance in short-term assays, clonogenic survival was inhibited after treatment. Gain of 20q11 was highly correlated with 19q12 amplification and spanned a 2.5 Mb region including TPX2, a centromeric protein required for mitotic spindle function. Expression of TPX2 was highly correlated with gene amplification and with CCNE1 expression in primary tumors. siRNA inhibition of TPX2 reduced cell viability but this effect was not amplicon-dependent. These findings demonstrate that CCNE1 is a key driver in the 19q12 amplicon required for survival and clonogenicity in cells with locus amplification. Co-amplification at 19q12 and 20q11 implies the presence of a cooperative mutational network. These observations have implications for the application of targeted therapies in CCNE1 dependent ovarian cancers. [ABSTRACT FROM AUTHOR]

Background: TRK-inhibitors have demonstrated efficacy across several cancers with NTRK fusions. Their activity in cancers with NTRK overexpression remains unclear., Methods: This trial enrolled patients with advanced cancers harboring NTRK fusions or extreme mRNA overexpression, defined as NTRK1/2/3 expression by RNA profiling >5 SDs for a given cancer type. The primary endpoint was objective response rate (ORR), with secondary endpoints including time-to-progression (TTP) ratio [TTP on study to TTP on previous systemic therapy (TTP1)], progression-free survival (PFS), and overall survival (OS). Initially planned for 2 non-comparator groups: primary central nervous system (CNS) and non-CNS tumours with NTRK fusions, the protocol was amended to permit NTRK overexpression., Results: Seventeen patients were treated with larotrectinib: one glioblastoma with a SPECC1L::NTRK2 fusion (group 1), and a peripheral nerve sheath tumor with a TPM3::NTRK1 fusion and 15 patients with overexpression (group 2). The ORR was 6%. An additional 3 of 12 (25%) TTP1-evaluable patients achieved a TTP ratio ≥1.3 and 2 of 5 without an evaluable TTP1 had a PFS >6 months. Median PFS and OS were 3.5 (95% CI, 1.4-6.0) and 15.9 months (95% CI, 6.4-NR), respectively., Conclusion: Unlike its efficacy in NTRK-fusion positive cancers, larotrectinib did not demonstrate a signal of efficacy among tumors with NTRK overexpression., (© The Author(s) 2024. Published by Oxford University Press.)

Cancer genetics has to date focused on epithelial malignancies, identifying multiple histotype-specific pathways underlying cancer susceptibility. Sarcomas are rare malignancies predominantly derived from embryonic mesoderm. To identify pathways specific to mesenchymal cancers, we performed whole-genome germline sequencing on 1644 sporadic cases and 3205 matched healthy elderly controls. Using an extreme phenotype design, a combined rare-variant burden and ontologic analysis identified two sarcoma-specific pathways involved in mitotic and telomere functions. Variants in centrosome genes are linked to malignant peripheral nerve sheath and gastrointestinal stromal tumors, whereas heritable defects in the shelterin complex link susceptibility to sarcoma, melanoma, and thyroid cancers. These studies indicate a specific role for heritable defects in mitotic and telomere biology in risk of sarcomas.