Briefly, our findings are summarized as follows: 1) HO-1 was present in silicotic nodules in both murine and human lung samples, 2) HO-1 acts in a protective role by attenuating lung inflammation, 3) induced HO-1 in the lungs of silicosis subjects could be detected in serum and thus be monitored, and 4) low serum HO-1 could predict accelerated lung function decline in chronic silicosis [20, 21]. This evidence concerns the gene HMOX1 and silicosis.