While the rat that developed mesothelioma in our study was found dead, and consequently could not be assessed for the presence of HMGB1 in the pleural cavity, the presence of a single visceral mesothelioma cannot be taken as evidence that administration of D15 into the lung resulted in translocation of D15 fibers into the pleural cavity and induction of mesothelioma by a mechanism relevant to humans. The gene discussed is HMGB1; the disease is mesothelioma.