NOTCH1, HIF1A and Other Cancer-Related Proteins in Lung Tissue from Uranium Miners—Variation by Occupational Exposure and Subtype of Lung Cancer

BackgroundRadon and arsenic are established pulmonary carcinogens. We investigated the association of cumulative exposure to these carcinogens with NOTCH1, HIF1A and other cancer-specific proteins in lung tissue from uranium miners. Methodology/Principal FindingsParaffin-embedded tissue of 147 miners was randomly selected from an autopsy repository by type of lung tissue, comprising adenocarcinoma (AdCa), squamous cell carcinoma (SqCC), small cell lung cancer (SCLC), and cancer-free tissue. Within each stratum, we additionally stratified by low or high level of exposure to radon or arsenic. Lifetime exposure to radon and arsenic was estimated using a quantitative job-exposure matrix developed for uranium mining. For 22 cancer-related proteins, immunohistochemical scores were calculated from the intensity and percentage of stained cells. We explored the associations of these scores with cumulative exposure to radon and arsenic with Spearman rank correlation coefficients (rs). Occupational exposure was associated with an up-regulation of NOTCH1 (radon rs = 0.18, 95% CI 0.02–0.33; arsenic: rs = 0.23, 95% CI 0.07–0.38). Moreover, we investigated whether these cancer-related proteins can classify lung cancer using supervised and unsupervised classification. MUC1 classified lung cancer from cancer-free tissue with a failure rate of 2.1%. A two-protein signature discriminated SCLC (HIF1A low), AdCa (NKX2-1 high), and SqCC (NKX2-1 low) with a failure rate of 8.4%. Conclusions/SignificanceThese results suggest that the radiation-sensitive protein NOTCH1 can be up-regulated in lung tissue from uranium miners by level of exposure to pulmonary carcinogens. We evaluated a three-protein signature consisting of a physiological protein (MUC1), a cancer-specific protein (HIF1A), and a lineage-specific protein (NKX2-1) that could discriminate lung cancer and its major subtypes with a low failure rate.研究背景 氡（Radon）与砷（arsenic）是公认的肺部致癌物。本研究以铀矿工的肺组织为研究对象，探究上述致癌物的累积暴露量与NOTCH1、HIF1A及其他癌症特异性蛋白之间的关联。方法与主要研究结果 本研究从尸检组织库中，按肺组织类型随机选取147例矿工的石蜡包埋组织，涵盖腺癌（adenocarcinoma, AdCa）、鳞状细胞癌（squamous cell carcinoma, SqCC）、小细胞肺癌（small cell lung cancer, SCLC）以及非癌肺组织。在每个组织类型层内，我们进一步按氡或砷的暴露水平高低进行分层。采用针对铀矿开采场景开发的定量职业暴露矩阵，估算矿工终生的氡与砷暴露量。针对22种癌症相关蛋白，我们根据染色细胞的染色强度与阳性细胞占比计算免疫组化评分。采用斯皮尔曼秩相关系数（Spearman rank correlation coefficient, rs）分析上述评分与氡、砷累积暴露量之间的关联。结果显示，职业暴露与NOTCH1的表达上调存在相关性（氡：rs=0.18，95%CI 0.02~0.33；砷：rs=0.23，95%CI 0.07~0.38）。此外，我们通过监督分类与非监督分类方法，探究了这些癌症相关蛋白能否用于肺癌分型。MUC1可区分肺癌组织与非癌肺组织，分类失败率为2.1%。基于双蛋白的特征模型可区分小细胞肺癌（HIF1A低表达）、腺癌（NKX2-1高表达）与鳞状细胞癌（NKX2-1低表达），分类失败率为8.4%。结论与研究意义 本研究结果表明，辐射敏感蛋白NOTCH1可随肺部致癌物暴露水平的升高，在铀矿工的肺组织中出现表达上调。我们评估了由生理蛋白MUC1、癌症特异性蛋白HIF1A与谱系特异性蛋白NKX2-1组成的三蛋白特征模型，该模型可低失败率地区分肺癌及其主要亚型。