ALB and neoplasm: Importantly, among the various polymethine cyanine dyes developed so far, which mainly consist of heptamethine or pentamethine cyanine skeletons, the heptamethine cyanine structure having a chloro-cyclohexenyl ring is much more favorable than other types of cyanine dyes in terms of in vivo tumor targetability enhanced by the formation of albumin adducts [10,11,12].