TROP2, encoded by TACSTD2 gene, is a transmembrane glycoprotein involved in the activation of the ERK/mitogen-activated protein kinase (MAPK) pathway, promoting cancer cell proliferation, migration, invasion, and survival, also by regulating the calcium ion signaling pathway, cyclin expression and Ki67 expression [34, 35] (Figure 1). The gene discussed is TACSTD2; the disease is cancer.