Before testing intraoperative molecular imaging with OTL38 in humans, folate receptor-alpha expression was confirmed to be present in 86% of pulmonary adenocarcinomas upon histopathologic review of 100 human pulmonary resection specimens.
We show that lung and pancreatic adenocarcinomas express the full spectrum of FR-α and FR-β combinations with ~76% of lung adenocarcinomas expressing both FR-α and FR-β while pancreatic cancers express primarily FR-β.
RNA scope, a novel chromogenic in situ hybridization assay tool, was used to examine expression of the alpha (FOLR1) and beta (FOLR2) isoforms of folate receptor relative to each other as well as to the macrophage markers CD11b and CD68, in samples of normal fallopian tube and fallopian adenocarcinoma as well as normal ovary and EOC.
While 74% of adenocarcinomas were positive for folate receptor alpha expression, our results found that only 13% of squamous cell carcinomas were FRA positive (p<0.0001).