Subtyping of Undifferentiated Non-small Cell Carcinomas in Bronchial Biopsy Specimens

IntroductionThe emergence of treatments for non-small cell lung carcinoma (NSCLC) with differential efficacy and toxicity between subtypes has highlighted the importance of specific pathologic NSCLC subtyping. Most NSCLCs are inoperable, and pathologic diagnosis is made only on small tissue samples that are prone to diagnostic inaccuracy. In a substantial proportion of cases, standard morphology cannot specifically subtype the tumor, necessitating a diagnosis of NSCLC-not otherwise specified (NOS). Histochemical staining for mucin and immunohistochemical (IHC) identification of NSCLC subtype-associated markers could help predict the final subtype of resected NSCLCs diagnosed as NSCLC-NOS on preoperative bronchial biopsy samples.MethodsParaffin sections of 44 bronchial biopsy samples diagnosed as NSCLC-NOS were stained for mucin (Alcian blue/periodic acid Schiff) and thyroid transcription factor 1 by IHC–(markers of adenocarcinoma), and for S100A7, cytokeratin 5/6, high molecular weight cytokeratins, and p63 proteins–markers of squamous cell carcinoma. A predictive staining panel was derived from statistical analysis after comparing staining profiles with the final postsurgical NSCLC subtype. This panel was prospectively applied to 82 small biopsy samples containing NSCLC.ResultsTrue NSCLC subtype of undifferentiated NSCLC samples was best predicted using Alcian blue/periodic acid Schiff plus p63 and thyroid transcription factor 1 IHC, allowing specific subtyping in 73% of NSCLC-NOS cases with 86% accuracy. When applied prospectively, this staining panel showed 100% concordance with specific NSCLC morphologic subtyping in small biopsies.ConclusionThis approach can facilitate treatment selection by accurately predicting the subtype in undifferentiated NSCLC biopsies, reducing to 7% the proportion of cases without a definite or probable histologic subtype

Serpin B3 is associated with poor survival after chemotherapy and is a potential novel predictive biomarker in advanced non-small-cell lung cancer

Introduction:In a previous biomarker discovery project using gene-expression profiling we identified Serpin B3 (SB3) as a predictor of resistance to platinum doublet chemotherapy (PtC) in non–small-cell lung cancer (NSCLC). This independent prospective study was designed to confirm the predictive utility of SB3.Methods:SB3 immunohistochemistry was scored by previously validated criteria (score 0 = negative, score 1 = 1%–10% tumor cells positive, score 2 = 11%–50% tumor cells positive, and score 3 = >50% tumor cell positive) in 197 patients with stage IV NSCLC treated with PtC. This provided 80% power to detect a median survival increase from 150 days in patients with an SB3 immunohistochemistry score of 2 or more to 300 days in those with an SB3 score of 0 or 1.Results:Thirty-six percent of NSCLCs stained positive for SB3. Median survival for SB3 negative/score 0 was 332 days, SB3 positive/score 1 was 268 days, and SB3 positive/score 2 or 3 was 120 days (p = 0.004). Cox proportional hazards analysis demonstrated that SB3 positivity is an independent predictor of survival (hazard ratio = 1.87; 95% confidence interval, 1.29–2.71; p = 0.001).The disease control rate in SB3 score 0, 1 = 65%, and score of 2 or more = 20 % (p = 0.002), with median survival 306 days (score 0, 1) versus 120 days (score ≥2, hazard ratio= 1.71; 95% confidence interval. 1.14–3.10; p = 0.002).Conclusions:SB3-positive immunohistochemistry score of 2 or more (>10% tumor cells positive) identifies a subgroup of patients with stage IV NSCLC who have a poor survival (median 120 days) when treated with PtC, similar to that estimated for untreated or chemo-refractory stage IV NSCLC. Further prospective qualification using biospecimens from randomized studies is needed, but SB3 seems to be a useful biomarker that identifies a highly resistant subgroup in whom PtC should be avoided

Mitochondrial peptide BRAWNIN is essential for vertebrate respiratory complex III assembly

The emergence of small open reading frame (sORF)-encoded peptides (SEPs) is rapidly expanding the known proteome at the lower end of the size distribution. Here, we show that the mitochondrial proteome, particularly the respiratory chain, is enriched for small proteins. Using a prediction and validation pipeline for SEPs, we report the discovery of 16 endogenous nuclear encoded, mitochondrial-localized SEPs (mito-SEPs). Through functional prediction, proteomics, metabolomics and metabolic flux modeling, we demonstrate that BRAWNIN, a 71 a.a. peptide encoded by C12orf73, is essential for respiratory chain complex III (CIII) assembly. In human cells, BRAWNIN is induced by the energy-sensing AMPK pathway, and its depletion impairs mitochondrial ATP production. In zebrafish, Brawnin deletion causes complete CIII loss, resulting in severe growth retardation, lactic acidosis and early death. Our findings demonstrate that BRAWNIN is essential for vertebrate oxidative phosphorylation. We propose that mito-SEPs are an untapped resource for essential regulators of oxidative metabolism