Mutation analysis of the HIF-1alpha oxygen-dependent degradation domain in invasive breast cancer.
Hypoxia inducible factor-1 (HIF-1) is an important transcription factor that stimulates tumor growth and metastases via several pathways. Activation of HIF-1 depends on the presence of its alpha-subunit. Hypoxia increases HIF-1alpha levels by inhibiting prolyl-hydroxylase--mediated hydroxylation and thereby preventing proteosome degradation. Various other mechanisms might also contribute to HIF-1alpha expression, such as mutation of the oxygen dependent degradation domain (ODD), which prevents binding of prolyl-hydroxylases. Therefore, the presence of ODD mutations was evaluated as a possible explanation for diffuse HIF-1alpha protein expression often seen in invasive breast cancer. From a group of 200 primary breast cancers, 24 strong diffusely HIF-1alpha-positive tumor samples were identified with HIF-1alpha immunohistochemistry. DNA from these tumors was extracted from microdissected paraffin material and, after nested polymerase chain reaction, sequence analysis was performed to detect hif-1alpha ODD mutations. Additionally, five perinecrotically HIF-1alpha-positive breast cancers were analyzed as controls. All 24 diffuse and perinecrotic HIF-1alpha-positive breast cancers showed wild-type DNA sequences in the ODD domain. No mutations seem to occur in the ODD of hif-1alpha in HIF-1alpha overexpressing invasive breast cancer, which rules ODD mutations out as a possible explanation for the diffuse HIF-1alpha expression pattern often seen in this cancer.
Vleugel
Marije M
MM
Department of Pathology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.
Greijer
Astrid E
AE
van der Wall
Elsken
E
van Diest
Paul J
PJ
D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D017931:DNA Primers; D005260:Female; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics*; D007150:Immunohistochemistry; D009154:Mutation; D009361:Neoplasm Invasiveness; D010100:Oxygen / Q000378:metabolism*; D016133:Polymerase Chain Reaction
D017931:DNA Primers; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010100:Oxygen