Lung cancer is the leading cause of cancer mortality worldwide with 1.8 million newly diagnosed cases, or 13% of all cancers diagnosed, in 2012 [1]. The worldwide numbers are still rising despite an ongoing small decline in the Western world. Global statistics estimate that 15% of lung cancers in men and 53% in women are not attributable to smoking, overall accounting for 25% [2].

Osimertinib is a third-generation, irreversible oral EGFR-tyrosine kinase inhibitor), that potently inhibits EGFR-tyrosine kinase inhibitor-sensitizing mutations and T790M resistance mutations toge... Lay abstract A plain language version of this article is available and is published alongside the paper online: www.futuremedicine.com/doi/suppl/10.2217/fon-2021-0549

PD-L1 expression on tumour cells can guide the use of anti-PD-1/PD-L1 immune modulators to treat patients with non-small cell lung cancer (NSCLC). Heterogeneity of PD-L1 expression both within and between tumour sites is a well-documented phenomenon that compromises its predictive power. Our aim was to better characterise the pattern and extent of PD-L1 heterogeneity with a view to optimising tumour sampling and improve its accuracy as a biomarker. Expression of PD-L1 was assessed by immunochemistry using the SP263 clone in 107 resected primary NSCLCs and their nodal metastases. Intra-tumoural heterogeneity, defined as 'small-scale' (mm²), 'medium-scale' (cm²) and 'large-scale' (between tumour blocks), was assessed by digital imaging using a novel 'squares method'. Inter-tumoural heterogeneity between the primary tumours and their nodal metastases and between N1 and N2 nodal stages was also assessed. The majority of tumours demonstrated intra-tumoural heterogeneity (small-scale 78%, medium-scale 50%, large-scale 46%). Inter-tumoural heterogeneity between the primary and nodal metastases was present in 53% of cases and, in 17%, between N1 and N2 disease. These differences were occasionally sufficient to lead to discrepancy across the ≥1%, ≥25% and ≥50% cut-offs used to guide therapy. Heterogeneity of PD-L1 expression is common, variable in scale and extent, and carries significant implications for its accuracy as a predictive biomarker. Extensive sampling reduces, but cannot eliminate, this inaccuracy.

The primary analysis of this trial showed that first-line treatment with osimertinib plus chemotherapy with a platinum-based agent and pemetrexed led to significantly longer progression-free survival than osimertinib monotherapy among patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC). Results from the planned final analysis of overall survival are needed. In this phase 3, international, open-label trial, we randomly assigned in a 1:1 ratio patients with EGFR-mutated (exon 19 deletion or L858R mutation) advanced NSCLC who had not previously received treatment for advanced disease to receive either osimertinib (80 mg once daily) plus chemotherapy with pemetrexed (500 mg per square meter of body-surface area) and a platinum-based agent (cisplatin [75 mg per square meter] or carboplatin [pharmacologically guided dose]) or osimertinib monotherapy (80 mg once daily). The key secondary end point was overall survival. A total of 557 patients were randomly assigned to the osimertinib plus platinum-pemetrexed group (279 patients) or the osimertinib monotherapy group (278 patients). The median overall survival was 47.5 months in the osimertinib plus platinum-pemetrexed group and 37.6 months in the osimertinib monotherapy group (hazard ratio for death, 0.77; 95% confidence interval, 0.61 to 0.96; P = 0.02). Grade 3 or higher adverse events of any cause were reported in 70% of the patients in the osimertinib plus platinum-pemetrexed group and in 34% of the patients in the osimertinib monotherapy group; adverse events leading to the discontinuation of osimertinib were reported in 12% and 7%, respectively. Among patients with EGFR-mutated advanced NSCLC, first-line treatment with osimertinib plus platinum-pemetrexed led to significantly longer overall survival than osimertinib monotherapy and was associated with an increased risk of reversible adverse events of grade 3 or higher. (Funded by AstraZeneca; FLAURA2 ClinicalTrials.gov number, NCT04035486.).

The androgen receptor (AR) is a major drug target in prostate cancer (PCa). We profiled the AR-regulated kinome to identify clinically relevant and druggable effectors of AR signaling. Using genome-wide approaches, we interrogated all AR regulated kinases. Among these, choline kinase alpha (CHKA) expression was evaluated in benign (n = 195), prostatic intraepithelial neoplasia (PIN) (n = 153) and prostate cancer (PCa) lesions (n = 359). We interrogated how CHKA regulates AR signaling using biochemical assays and investigated androgen regulation of CHKA expression in men with PCa, both untreated (n = 20) and treated with an androgen biosynthesis inhibitor degarelix (n = 27). We studied the effect of CHKA inhibition on the PCa transcriptome using RNA sequencing and tested the effect of CHKA inhibition on cell growth, clonogenic survival and invasion. Tumor xenografts (n = 6 per group) were generated in mice using genetically engineered prostate cancer cells with inducible CHKA knockdown. Data were analyzed with χ ² tests, Cox regression analysis, and Kaplan-Meier methods. All statistical tests were two-sided. CHKA expression was shown to be androgen regulated in cell lines, xenografts, and human tissue (log fold change from 6.75 to 6.59, P = .002) and was positively associated with tumor stage. CHKA binds directly to the ligand-binding domain (LBD) of AR, enhancing its stability. As such, CHKA is the first kinase identified as an AR chaperone. Inhibition of CHKA repressed the AR transcriptional program including pathways enriched for regulation of protein folding, decreased AR protein levels, and inhibited the growth of PCa cell lines, human PCa explants, and tumor xenografts. CHKA can act as an AR chaperone, providing, to our knowledge, the first evidence for kinases as molecular chaperones, making CHKA both a marker of tumor progression and a potential therapeutic target for PCa.