We verified that TRPV1 on SNs is activated by the 4T1 BC acidic microenvironment by showing increased expression of Ca2+/calmodulin-dependent protein kinase II (CAMKII), a TRPV1 downstream signal molecule 29, in the 50B11 rat immortalized DRG SN cell line 30 that was treated with acidic 4T1 BC CM or hydrochloric acid (pH 6.5) (Fig. 2D). The gene discussed is TRPV1; the disease is breast cancer.