Cinobufacini injection was aqueous extract of toad (Bufo) dried skin, which has been widely used for cancer therapy in China. Recent studies indicated that the antitumor components included in cinobufacini are polypeptides. To identify these components, the skin plasmid cDNA library of Japanese toad (B. japonicus formosus) was screened. One of the transcripts is 864 base pair (bp) consisting of 144 bp 5'-untranslated region (UTR), 384 bp 3'-UTR and an open reading frame (ORF) of 336 bp encoding a polypeptide of 111 amino acid residues. Homology analysis indicated 86% homolog with pancreatic progenitor cell differentiation and proliferation factor (PPDPF) of Xenopus laevis, which implicated in pancreas development. PPDPF ORF of Chinese toad (B. gargarizans) was cloned from its skin first strand cDNA encoding completely the same polypeptide as that of Japanese toad. Real-time quantitative polymerase chain reaction (qPCR) indicated PPDPF expressed in all organs of Chinese toad tested so far, while the highest expression is detected from pancreas. Considering the previous reports on the relevance of abnormal expression of PPDPF with several cancers including pancreatic cancer, PPDPF might be one of the crucial antitumor components of Bufo skin, so the successful cloning of PPDPF from Bufo skin is likely to shed light on some new antitumor drug development in future.