Immune checkpoint blockade (ICB) improves outcomes in non-small cell lung cancer (NSCLC) though most patients progress. There are limited data regarding molecular predictors of progression. In particular, there is controversy regarding the role of CDKN2A loss-of-function (LOF) in ICB resistance. We analyzed 139 consecutive patients with advanced NSCLC who underwent NGS prior to ICB initiation to explore the association of CDKN2A LOF with clinical outcomes. 73% were PD-L1 positive (≥ 1%). 48% exhibited high TMB (≥ 10 mutations/megabase). CDKN2A LOF was present in 26% of patients and was associated with inferior PFS (multivariate hazard ratio [MVA-HR] 1.66, 95% CI 1.02–2.63, p = 0.041) and OS (MVA-HR 2.08, 95% CI 1.21–3.49, p = 0.0087) when compared to wild-type (WT) patients. These findings held in patients with high TMB (median OS, LOF vs. WT 10.5 vs. 22.3 months; p = 0.069) and PD-L1 ≥ 50% (median OS, LOF vs. WT 11.1 vs. 24.2 months; p = 0.020), as well as in an independent dataset. CDKN2A LOF vs. WT tumors were twice as likely to experience disease progression following ICB (46% vs. 21%; p = 0.021). CDKN2A LOF negatively impacts clinical outcomes in advanced NSCLC treated with ICB, even in high PD-L1 and high TMB tumors. This novel finding should be prospectively validated and presents a potential therapeutic target.
Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate cancer. Our lab and others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate cancer.
Early stage glottic cancer has traditionally been treated with 3D conformal radiotherapy (3DCRT). However, intensity-modulated radiotherapy (IMRT) has been recently adopted as an alternative to decrease toxicity. Here, we compared the usage and outcomes of IMRT and 3DCRT for patients with early stage squamous cell carcinoma (SCC) of the glottic larynx. Using the National Cancer Database, we identified patients with Stage I–II SCC of the glottis who received 55–75 Gy using IMRT (n = 1623) or 3DCRT (n = 2696). Median follow up was 42 months with a 5-year overall survival (OS) of 72%. Using a nominal logistic regression, race, ethnicity, year of diagnosis and fraction size were associated with the receipt of IMRT (p < 0.05). Using Kaplan–Meier methods and Cox proportional hazards models as well as a propensity matched cohort, there was no difference in OS for patients who received IMRT versus 3DCRT (hazard ratio (HR), 1.08; 95% confidence interval (95% CI), 0.93–1.26; p = 0.302). However, there was a survival benefit for patients receiving slight hypofractionation as compared to conventional fractionation (HR, 0.78; 95% CI, 0.69–0.92; p = 0.003). IMRT was associated with similar survival as 3DCRT, supporting the implementation of this potentially less toxic modality without compromising survival.
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