Abstract: An isoform of the TGF beta receptor II comprising a sequence of about of 80 amino acids and lacking a transmembrane domain. The isoform comprises the amino acid sequence set forth in SEQ ID No. 12. The isoform may have the amino acid sequence set forth in SEQ ID No. 2 or sequences having at least 85% sequence identity to the sequence set forth in SEQ ID No. 2. A fusion peptide is provided comprising an isoform of the TGF beta II receptor fused to a ligand, wherein a vector comprising the fusion peptide is used to treat cancer and/or hepatic fibrosis. An antibody binding the soluble isoform of the TGF beta II receptor is provided. The antibody binds the amino acid sequence shown in SEQ ID No. 12 and is used in in vitro methods.