Regarding tumor ECs, one study identified two populations, IGFBP3+ ECs and SPRY1+ ECs (27), another study defined IGFBP7+PLVAP+ as tumor ECs, with high expression of HSPG2 and POSTN, which are associated with angiogenesis (19), and another study suggested that tumor ECs highly express insulin receptor (INSR) and HSPG2. Here, HSPG2 is linked to neoplasm.