CYP1A1 and pulmonary arterial hypertension: In this respect, the use of other techniques such as immunochemical detection of PAH‐specific DNA damage in target tissues [Machella et al. 2005] or measurement of CYP1A1 expression [Wilson et al. 2005], as well as controlled laboratory exposures of porpoise hepatic cells to individual contaminants or mixtures of the specific components, might help to identify the exact compound(s) responsible for the adducts observed.