“…FR-a is highly expressed in tumor cell lines including among others, those of ovarian, kidney (MA104), colon (Caco-2), and epidermoid (KB) origin (Coney et al, 1991;Weitman et al, 1992a). FR-a is overexpressed in a variety of human neoplastic tissues, such as carcinomas of the ovary, uterus, brain, and squamous cell carcinoma of the head and neck (Campbell et al, 1991;Coney et al, 1991;Weitman et al, 1992ba, 1994Ross et al, 1994;Miotti et al, 1995;Wu et al, 1999). In contrast, FR-b expression is much more restricted.…”