While in pulmonary lymphangioleiomyomatosis, CTSK is a better prognostic marker [14], in colorectal cancer, it acts as a mediator between gut microbiota imbalance and tumor metastasis [20], and in prostate cancer, it affects tumor migration and invasion through the IL-17/CTSK axis, making it a potential therapeutic target [15]. The gene discussed is IL17A; the disease is colorectal cancer.