Radiation-induced effects on gene expression: an in vivo study on breast cancer.
OBJECTIVE
Breast cancer is diagnosed worldwide in approximately one million women annually and radiation therapy is an integral part of treatment. The purpose of this study was to investigate the molecular basis underlying response to radiotherapy in breast cancer tissue.


METHODS
Tumour biopsies were sampled before radiation and after 10 treatments (of 2 Gray (Gy) each) from 19 patients with breast cancer receiving radiation therapy. Gene expression microarray analyses were performed to identify in vivo radiation-responsive genes in tumours from patients diagnosed with breast cancer. The mutation status of the TP53 gene was determined by using direct sequencing.


CONCLUSIONS
Several genes involved in cell cycle regulation and DNA repair were found to be significantly induced by radiation treatment. Mutations were found in the TP53 gene in 39% of the tumours and the gene expression profiles observed seemed to be influenced by the TP53 mutation status.
Helland
Aslaug
A
Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway. ahelland@labmed.uio.no <ahelland@labmed.uio.no>
Johnsen
Hilde
H
Frøyland
Caroline
C
Landmark
Hege B K
HB
Saetersdal
Anna B
AB
Holmen
Marit Muri
MM
Gjertsen
Turid
T
Nesland
Jahn M
JM
Ottestad
William
W
Jeffrey
Stefanie S
SS
Ottestad
Lars O
LO
Rodningen
Olag K
OK
Sherlock
Gavin
G
Børresen-Dale
Anne-Lise
AL
D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000532:radiotherapy*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000528:radiation effects; D016158:Genes, p53 / Q000528:radiation effects*; D006801:Humans; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C117669:DDB2 protein, human; D004268:DNA-Binding Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53