Palb2 synergizes with Trp53 to suppress mammary tumor formation in a model of inherited breast cancer

Proc Natl Acad Sci U S A. 2013 May 21;110(21):8632-7. doi: 10.1073/pnas.1305362110. Epub 2013 May 8.


Germ-line mutations in PALB2 lead to a familial predisposition to breast and pancreatic cancer or to Fanconi Anemia subtype N. PALB2 performs its tumor suppressor role, at least in part, by supporting homologous recombination-type double strand break repair (HR-DSBR) through physical interactions with BRCA1, BRCA2, and RAD51. To further understand the mechanisms underlying PALB2-mediated DNA repair and tumor suppression functions, we targeted Palb2 in the mouse. Palb2-deficient murine ES cells recapitulated DNA damage defects caused by PALB2 depletion in human cells, and germ-line deletion of Palb2 led to early embryonic lethality. Somatic deletion of Palb2 driven by K14-Cre led to mammary tumor formation with long latency. Codeletion of both Palb2 and Tumor protein 53 (Trp53) accelerated mammary tumor formation. Like BRCA1 and BRCA2 mutant breast cancers, these tumors were defective in RAD51 focus formation, reflecting a defect in Palb2 HR-DSBR function, a strongly suspected contributor to Brca1, Brca2, and Palb2 mammary tumor development. However, unlike the case of Brca1-mutant cells, Trp53bp1 deletion failed to rescue the genomic instability of Palb2- or Brca2-mutant primary lymphocytes. Therefore, Palb2-driven DNA damage control is, in part, distinct from that executed by Brca1 and more similar to that of Brca2. The mechanisms underlying Palb2 mammary tumor suppression functions can now be explored genetically in vivo.

Keywords: familial breast cancer; mouse model.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism
  • BRCA2 Protein / genetics
  • BRCA2 Protein / metabolism
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Disease Models, Animal
  • Fanconi Anemia Complementation Group N Protein
  • Female
  • Gene Deletion
  • Humans
  • Mammary Neoplasms, Experimental / genetics
  • Mammary Neoplasms, Experimental / metabolism*
  • Mammary Neoplasms, Experimental / pathology
  • Mice
  • Mice, Mutant Strains
  • Neoplastic Syndromes, Hereditary / genetics
  • Neoplastic Syndromes, Hereditary / metabolism*
  • Neoplastic Syndromes, Hereditary / pathology
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Rad51 Recombinase / genetics
  • Rad51 Recombinase / metabolism
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*


  • BRCA1 Protein
  • BRCA1 protein, human
  • BRCA2 Protein
  • BRCA2 protein, human
  • BRCA2 protein, mouse
  • Fanconi Anemia Complementation Group N Protein
  • Nuclear Proteins
  • PALB2 protein, human
  • Palb2 protein, mouse
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • RAD51 protein, human
  • Rad51 Recombinase
  • Rad51 protein, mouse