Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, resulting in hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1). Transcription factor EB (TFEB), a master regulator of lysosome biogenesis, is negatively regulated by mTORC1 through a RAG GTPase-dependent phosphorylation. Here we show that lysosomal biogenesis is increased in TSC-associated renal tumors, pulmonary lymphangioleiomyomatosis, kidneys from Tsc2+/− mice, and TSC1/2-deficient cells via a TFEB-dependent mechanism. Interestingly, in TSC1/2-deficient cells, TFEB is hypo-phosphorylated at mTORC1-dependent sites, indicating that mTORC1 is unable to phosphorylate TFEB in the absence of the TSC1/2 complex. Importantly, overexpression of folliculin (FLCN), a GTPase activating protein for RAGC, increases TFEB phosphorylation at the mTORC1 sites in TSC2-deficient cells. Overexpression of constitutively active RAGC is sufficient to relocalize TFEB to the cytoplasm. These findings establish the TSC proteins as critical regulators of lysosomal biogenesis via TFEB and RAGC and identify TFEB as a driver of the proliferation of TSC2-deficient cells.

Purpose: Immune checkpoint inhibitors (ICI) have shown clinical benefit in many types of metastatic cancers with only a few predictive biomarkers identified so far. CDKN2A is commonly altered in human cancers, but prior studies have provided conflicting evidence regarding the association between CDKN2A genomic alterations (GA) and response to ICIs. Herein, we examined the impact of loss-of-function CDKN2A alterations on response and survival in patients treated with ICIs. Experimental Design: We studied the association between loss-of-function CDKN2A alterations and the response to ICIs in two independent cohorts of six different cancer types. Seven hundred and eighty-nine patients treated at Dana-Farber Cancer Institute (DFCI; Boston, MA) and 1,250 patients treated at Memorial Sloan Kettering Cancer Center (MSKCC; New York, NY) were included in the final analysis. Patients' tumors were sequenced using Oncopanel or MSK-IMPACT. RNA sequencing data from The Cancer Genome Atlas and IMvigor210 were used to investigate differences in the tumor microenvironment. Results: In the DFCI cohort, CDKN2A GAs were associated with poor response and survival in patients with urothelial carcinoma treated with ICIs, but not those treated with platinum-based therapy. Similarly, CDKN2A GAs were associated with worse outcomes in the MSKCC urothelial carcinoma cohort treated with ICIs. There was no association of CDKN2A status with ICI treatment outcome in five other cancers: esophagogastric, head and neck, non–small cell lung, renal cell carcinoma, and melanoma. Immuno-inflammatory pathways were significantly reduced in expression in CDKN2A-altered tumors. Conclusions: Our data show that CDKN2A GAs were associated with reduced benefit from ICI therapy in urothelial carcinoma as well as changes in the tumor–immune microenvironment.

No abstract

Background Genomic alterations in 8 genes are now the targets of FDA-approved therapeutics in non-small cell lung cancer (NSCLC), but their distribution according to genetic ancestry, sex, histology, and smoking is not well established. Methods Using multi-institutional genetic testing data from GENIE, we characterize the distribution of targetable genomic alterations in 8 genes among 8675 patients with NSCLC (discovery cohort: DFCI, N = 3115; validation cohort: Duke, Memorial Sloan Kettering Cancer Center, Vanderbilt, N = 5560). For the discovery cohort, we impute genetic ancestry from tumor-only sequencing and identify differences in the frequency of targetable alterations across ancestral groups, smoking pack-years, and histologic subtypes. Results We identified variation in the prevalence of KRASG12C, sensitizing EGFR mutations, MET alterations, ALK, and ROS1 fusions according to the number of smoking pack-years. A novel method for computing continental (African, Asian, European) and Ashkenazi Jewish ancestries from panel sequencing enables quantitative analysis of the correlation between ancestry and mutation rates. This analysis identifies a correlation between Asian ancestry and EGFR mutations and an anti-correlation between Asian ancestry and KRASG12C mutation. It uncovers 2.7-fold enrichment for MET exon 14 skipping mutations and amplifications in patients of Ashkenazi Jewish ancestry. Among never/light smokers, targetable alterations in LUAD are significantly enriched in those with Asian (80%) versus African (49%) and European (55%) ancestry. Finally, we show that 5% of patients with squamous cell carcinoma (LUSC) and 17% of patients with large cell carcinoma (LCLC) harbor targetable alterations. Conclusions Among patients with NSCLC, there was significant variability in the prevalence of targetable genomic alterations according to genetic ancestry, histology, and smoking. Patients with LUSC and LCLC have 5% rates of targetable alterations supporting consideration for sequencing in those subtypes.