Tumorigenicity assay in nude mice

Animal experiments were undertaken with the approval of the Institutional Committee for Animal Research and in conformity with national guidelines for the care and use of laboratory animals. The UCA1‐si and Ctrl‐si transfected SCC15 cells (1 × 10⁷ cells in 200 μL) were injected s.c. into the flanks of 4‐week‐old male athymic nude mice (Experimental Animal Center, Guangdong, China). Tumor growth was examined weekly for at least 6 weeks. Then the mice were killed, necropsies were carried out, and tumors were weighed. Tumor volumes were calculated by the formula: V = πLW²/6, where L is the largest diameter, and W is the perpendicular diameter.