NT5E and pulmonary fibrosis: Similarly, a model of lung fibrosis induced by a single dose (15 Gray) of chest area irradiation in WT and CD73−/− (Nt5e−/−) mice showed that CD73 plays an essential role in the development of fibrosis and that treatment with radiation leads to a gradual increase in CD73 activity in the lung between 3 and 30 weeks after treatment in WT mice, with a more significant increase observed between 25 and 30 weeks, at which time there was a greater degree of fibrosis.