Victor T. G. Lin

Background: Next-generation sequencing (NGS) testing in patients with metastatic non-small cell lung cancer (mNSCLC) identifies actionable driver oncogenes (ADO) and targeted treatment (TT). Potential inequities were evaluated in NGS testing and TT in patients with mNSCLC. Patients and methods: This retrospective study used a nationwide electronic health record–derived deidentified database for patients ≥18 years diagnosed with mNSCLC between 4/2018 and 4/2024, ≥2 recorded visits, and follow-up ≥90 days post diagnosis. For TT, patients must have received NGS testing before first-line (1L) treatment and harbored ≥1 1L ADO. Results: A total of 15 392 patients with mNSCLC were included: 66% with commercial insurance, 16% with Medicare, 12% with other, 4% with Medicaid, and 3% with other government insurance. Patients with commercial insurance had significantly higher odds of receiving NGS testing vs Medicare, Medicaid, or other insurance. While patient characteristics varied across insurances, the effect of insurance type on NGS testing did not differ by race/ethnicity, age, or socioeconomic status (SES). Site of care was a significant effect modifier, with increased odds of NGS testing for community vs academic settings for commercial, Medicare, and other insurance and decreased odds for Medicaid. When all patients received NGS testing, significantly lower odds of receiving TT occurred for patients with SES 2 vs SES 1 (lowest); higher odds occurred for Asian vs white patients. Conclusion: Insurance is a key contributor to inequity in NGS testing. When all patients received NGS testing, equity was achieved in patients receiving TT, except those with lower SES, who potentially did not qualify for Medicaid.

Ribosomal DNA (rDNA) consists of highly repeated sequences that are prone to incurring damage. Delays or failure of rDNA double-strand break (DSB) repair are deleterious, and can lead to rDNA transcriptional arrest, chromosomal translocations, genomic losses, and cell death. Here, we show that the zinc-finger transcription factor GLI1, a terminal effector of the Hedgehog (Hh) pathway, is required for the repair of rDNA DSBs. We found that GLI1 is activated in triple-negative breast cancer cells in response to ionizing radiation (IR) and localizes to rDNA sequences in response to both global DSBs generated by IR and site-specific DSBs in rDNA. Inhibiting GLI1 interferes with rDNA DSB repair and impacts RNA polymerase I activity and cell viability. Our findings tie Hh signaling to rDNA repair and this heretofore unknown function may be critically important in proliferating cancer cells.

The treatment of cancer continues to evolve toward personalized therapies based on individual patient and tumor characteristics. Our successes and failures in adopting a precision-oncology approach have demonstrated the utmost importance in identifying the proper predictive biomarkers of response. Until recently, most biomarkers were identified using immunohistochemistry for protein expression or single-gene analysis to identify targetable alterations. With the rapid propagation of next-generation sequencing to evaluate tumor tissue and “liquid biopsies,” identification of genomic biomarkers is now standard, particularly in non–small cell lung cancer, for which there is now an extensive catalog of biomarker-directed therapies with more anticipated to come. Despite these great strides, it has also become apparent that using genomic biomarkers alone will be insufficient, as it has been consistently shown that at least one-half of patients who undergo tumor genomic profiling have no actionable alteration. This is perhaps to be expected given the remarkable breadth of nongenetic factors that contribute to tumor initiation and progression. Some have proposed that the next logical step is to use transcriptome profiling to define new biomarkers of response to targeted agents. Recently, results from the WINTHER trial were published, specifically investigating the use of transcriptomics to improve match rates over genomic next-generation sequencing alone. In this review, we discuss the complexities of precision-oncology efforts and appraise the available evidence supporting the incorporation of transcriptomic data into the precision-oncology framework in the historical context of the development of biomarkers for directing cancer therapy.

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy for which limited data exist to guide treatment decisions. With the advent of advanced molecular testing and tumor genomic profiling, clinicians now have the ability to identify potential therapeutic targets in difficult-to-treat cancers such as SDC. This report presents a male patient with widely metastatic SDC found on targeted next-generation sequencing to have a BRAF p.V600E mutation. He experienced a prolonged and robust response to first-line systemic chemotherapy with dabrafenib and trametinib. During his response interval, new data emerged to justify subsequent treatment with both an immune checkpoint inhibitor and androgen blockade after his disease progressed. To our knowledge, this is the first report of frontline BRAF-directed therapy eliciting a response in metastatic SDC.

The elevated lysophosphatidic acid signaling has been causally linked to cancer-associated inflammation and tumorigenesis through upregulation of nuclear factor-κB signaling. However, how this signaling event is regulated has not yet been fully understood. Here we demonstrate that TRIP6, an LPA2 receptor-interacting adaptor protein, functions as a positive regulator of nuclear factor-κB and JNK signaling through direct binding to and activation of the E3 ligase TRAF6. Upon lysophosphatidic acid stimulation, TRIP6 recruits TRAF6 to the LPA2 receptor and promotes lysophosphatidic acid-induced JNK and nuclear factor-κB activation in a TRAF6-dependent manner. TRIP6 antagonizes the recruitment of deubiquitinases A20 and CYLD to TRAF6, thus sustaining the E3 ligase activity of TRAF6 and augmenting lysophosphatidic acid-activated nuclear factor-κB signaling. In contrast, depletion of TRIP6 by TRIP6-specific shRNA or Cas9/sgRNA greatly enhances the association of TRAF6 with A20 and CYLD, and attenuates lysophosphatidic acid-induced muclear factor-κB and JNK/p38 activation in ovarian cancer cells. On the other hand, TRAF6 also regulates TRIP6 by facilitating its binding to nuclear factor-κB p65 and phosphorylation by c-Src. Together, TRIP6 cooperates with TRAF6 to regulate the LPA2 receptor signaling, which may ultimately contribute to chronic inflammation, apoptotic resistance and cell invasion.

TRIP6 is an adaptor protein that regulates cell motility and antiapoptotic signaling. Although it has been implicated in tumorigenesis, the underlying mechanism remains largely unknown. Here we provide evidence that TRIP6 promotes tumorigenesis by serving as a bridge to promote the recruitment of p27(KIP1) to AKT in the cytosol. TRIP6 regulates the membrane translocation and activation of AKT and facilitates AKT-mediated recognition and phosphorylation of p27(KIP1) specifically at T157, thereby promoting the cytosolic mislocalization of p27(KIP1). This is required for p27(KIP1) to enhance lysophosphatidic acid (LPA)-induced ovarian cancer cell migration. TRIP6 also promotes serum-induced reduction of nuclear p27(KIP1) expression levels through Skp2-dependent and -independent mechanisms. Consequently, knockdown of TRIP6 in glioblastoma or ovarian cancer xenografts restores nuclear p27(KIP1) expression and impairs tumor proliferation. As TRIP6 is upregulated in gliomas and its levels correlate with poor clinical outcomes in a dose-dependent manner, it may represent a novel prognostic marker and therapeutic target in gliomas.

The Fas/CD95 receptor mediates apoptosis but is also capable of triggering nonapoptotic signals. However, the mechanisms that selectively regulate these opposing effects are not yet fully understood. Here we demonstrate that the activation of Fas or stimulation with lysophosphatidic acid (LPA) induces cytoskeletal reorganization, leading to the association of Fas with actin stress fibers and the adaptor protein TRIP6. TRIP6 binds to the cytoplasmic juxtamembrane domain of Fas and interferes with the recruitment of FADD to Fas. Furthermore, through physical interactions with NF-κB p65, TRIP6 regulates nuclear translocation and the activation of NF-κB upon Fas activation or LPA stimulation. As a result, TRIP6 antagonizes Fas-induced apoptosis and further enhances the antiapoptotic effect of LPA in cells that express high levels of TRIP6. On the other hand, TRIP6 promotes Fas-mediated cell migration in apoptosis-resistant glioma cells. This effect is regulated via the Src-dependent phosphorylation of TRIP6 at Tyr-55. As TRIP6 is overexpressed in glioblastomas, this may have a significant impact on enhanced NF-κB activity, resistance to apoptosis, and Fas-mediated cell invasion in glioblastomas.