FLT4 and squamous cell carcinoma: In a study of the expression of VEGF-C and VEGF-D, as well as their receptor VEGFR-3, in 152 lesions of the cervix (33 CIN 1, 33 CIN 2, 37 CIN 3, and 49 squamous cell carcinomas), the expression of the VEGFR3 protein was found in more than 50% of lesions in CIN 3 and cervical cancer, compared with 15% in CIN 1 and 2, which indicates that during cervical carcinogenesis, the switch to the lymphangiogenic phenotype may occur at the stage of CIN 3 before the onset of invasion [67].