GDF11 and lung cancer: Four of the seven human homologs of KEX2 were UES in the pharmacogenomics analysis (Figure 6D; 1-0-10), including: (1) PCSK1, which can be downregulated by pancreatic cancer derived exosomes [176], (2) PCSK2, which has reduced expression in lung cancer [177], (3) PCSK5, which is also reduced in lung cancer and, furthermore, when reduced in triple negative breast cancer, leads to loss of the Gdf11 tumor suppressor [177,178], and (4) PCSK7, which has been reported both to have reduced expression in lung cancer and increased expression in gemcitabine-resistant cells [177,179].