POSTN and neoplasm: However, this type of test still has certain disadvantages, such as being static and not capturing distribution/metabolism at the organism level [76], and in vivo tumors have albumin, fibrinogen/fibrin, and other plasma proteins in the tumor interstitial fluid (TIF) [77] and accumulate hyaluronan, tenascin-C, periostin, collagen I/III [78], which do not exist in spheroids.