Studies have also shown that the expression of HSP90 in serum exosomes of cancer patients with highly metastatic CCA is significantly higher than that in patients with common CCA, suggesting that the level of HSP90 in serum exosomes is related to the malignant degree of the tumor, probably due to the fact that HSP90 contributes to tumor metastasis and invasion by activating related proteins in the extracellular microenvironment. The gene discussed is HSP90AB1; the disease is neoplasm.