Hyper-radiosensitivity affects low-dose acute myeloid leukemia incidence in a mathematical model

Area of Science:

• Radiobiology
• Cancer Research
• Genetics

Background:

• Cells implicated in radiation-induced acute myeloid leukemia (rAML) exhibit low-dose hyper-radiosensitivity (HRS).
• HRS is known to cause increased cell killing and chromosomal aberrations, like deletions, at low radiation doses.
• The impact of HRS on low-dose cancer risk remains largely uncharacterized.

Purpose of the Study:

• To investigate and quantify potential mechanisms by which HRS influences low-dose rAML incidence in CBA mice.
• To model HRS-dependent acute myeloid leukemia onset following low-dose photon irradiation.

Main Methods:

• Development of a mechanistic rAML CBA mouse model to study HRS.
• Computation of rAML incidence under three scenarios: no HRS, HRS affecting cell killing only, and HRS affecting both cell killing and Sfpi1 deletion formation.
• Analysis of dose-response curves using linear-quadratic functions.

Main Results:

• In the absence of HRS, rAML incidence followed a linear-quadratic dose-response relationship.
• Assuming HRS solely enhances cell killing reduced rAML incidence compared to the control.
• When HRS was assumed to enhance both cell killing and Sfpi1 deletion formation, rAML incidence increased at low doses.

Conclusions:

• Cellular HRS influences the survival of pre-leukemic cells with Sfpi1 deletions, directly impacting rAML probability.
• The effect of HRS on rAML incidence is dependent on its role in cell killing versus genetic alteration.
• Low-dose HRS may generally modify cancer risk by altering the occurrence or persistence of specific mutations.