SPP1 and tongue cancer: Using the method developed by Matsuzaki et al. [130], OPN expression still significantly related to the expression of VEGF and CD105 (both P < .001), tumour invasion depth (P = .001), and regional nodal metastases (P < .001), and Chien et al. [131] confirmed the relationship between OPN and VEGF, thus suggesting their importance in the development of new vessels in early tongue cancer.