PCSK9 and lung cancer: Conversely, PCSK9 mRNA expression was substantially lower in lung cancers (lung adenocarcinoma [LUAD] and squamous cell carcinoma [LUSC]), kidney cancers (kidney renal clear cell carcinoma [KIRC] and papillary cell carcinoma [KIRP]), and prostate adenocarcinoma (PRAD) (Fig. 2b).