There are various sources of ionizing radiation exposure, where medical
exposure for radiation therapy or diagnosis is the most common human-made
source. Understanding how gene expression is modulated after ionizing radiation
exposure and investigating the presence of any dose-dependent gene expression
patterns have broad implications for health risks from radiotherapy, medical
radiation diagnostic procedures, as well as other environmental exposure. In
this paper, we perform a comprehensive pathway-based analysis of gene
expression profiles in response to low-dose radiation exposure, in order to
examine the potential mechanism of gene regulation underlying such responses.
To accomplish this goal, we employ a statistical framework to determine whether
a specific group of genes belonging to a known pathway display coordinated
expression patterns that are modulated in a manner consistent with the
radiation level. Findings in our study suggest that there exist complex yet
consistent signatures that reflect the molecular response to radiation
exposure, which differ between low-dose and high-dose radiation.