FLT4 and breast carcinoma: Its activation through some specific RTKs (receptor tyrosine kinase), in our case PDGFRB—class III, VEGFR3 (FLT4)—class IV, FGFR2—class V, and TEK—class IX, certifies its involvement in breast cancer progression, and its abnormal activation by ERBB2 is related with the development of human breast cancers and mammary carcinoma [21] (Figure 2B).