hSP, the domain-duplicated homolog of pS2 protein, is co-expressed with pS2 in stomach but not in breast carcinoma

EMBO J. 1990 Feb;9(2):407-14.


Approximately 50% of human breast tumors secrete a small cysteine-rich protein, pS2, of unknown function. pS2 protein was recently found to be homologous to a porcine protein with hormonogastric activity, pancreatic spasmolytic polypeptide (PSP), in which the 5-cysteine domain present in pS2 is tandemly duplicated. We have characterized cDNA species encoding PSP and its human and mouse counterparts, hSP and mSP. We show that hSP and pS2 are separately encoded in the genome, and that the two proteins are co-expressed in normal stomach epithelium. However, expression of hSP was not detected in breast tumors. Computer analysis revealed that the pattern of conserved cysteine residues in hSP and pS2, the P domain, is present at the N termini of two other mammalian proteins, intestinal sucrase-isomaltase and lysosomal alpha-glucosidase.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biological Evolution
  • Blotting, Southern
  • Breast Neoplasms / genetics*
  • Cloning, Molecular
  • DNA, Neoplasm / genetics
  • Female
  • Gene Expression
  • Gene Library
  • Humans
  • Intercellular Signaling Peptides and Proteins
  • Mice
  • Molecular Sequence Data
  • Mucins*
  • Muscle Proteins*
  • Neoplasm Proteins / genetics*
  • Neuropeptides*
  • Nucleic Acid Hybridization
  • Peptides / genetics*
  • Proteins*
  • RNA, Neoplasm / genetics
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Stomach Neoplasms / genetics*
  • Swine
  • Trefoil Factor-1
  • Trefoil Factor-2
  • Trefoil Factor-3
  • Tumor Suppressor Proteins


  • DNA, Neoplasm
  • Intercellular Signaling Peptides and Proteins
  • Mucins
  • Muscle Proteins
  • Neoplasm Proteins
  • Neuropeptides
  • Peptides
  • Proteins
  • RNA, Neoplasm
  • TFF1 protein, human
  • TFF3 protein, rat
  • Tff2 protein, rat
  • Trefoil Factor-1
  • Trefoil Factor-2
  • Trefoil Factor-3
  • Tumor Suppressor Proteins
  • pancreatic spasmolytic polypeptide