Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds which are emitted through incomplete combustion of organic materials, fossil fuels, consumption of processed meat, smoked food, and from various industrial activities. High molecular mass and mobility make PAHs widespread and lethal for human health. A cellular system in human detoxifies these toxicants through specialized enzymatic machinery called xenobiotic-metabolizing (CYP450) and phase-II (GSTs) enzymes (XMEs). These metabolizing enzymes include cytochromes P450 family (CYP1, CYP2), glutathione s-transferases, and ALDHs. Gene polymorphisms in XMEs encoding genes can compromise their metabolizing capacity to detoxify ingested carcinogens (PAHs etc.) that may lead to prolong and elevated exposure to ingested toxicants and may consequently lead to cancer. Moreover, PAHs can induce cancer through reprograming XMEs' gene functions by altering their epigenetic markers. This review article discusses possible interplay between individual's gene polymorphism in XMEs' genes, their altered epigenetic markers, and exposure to PAHs in cancer susceptibility in Pakistan.

中文翻译：

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从环境，职业和遗传的角度来看，高暴露于多环芳烃（PAHs）可能在巴基斯坦引发癌症。

多环芳烃（PAH）是致癌化合物，其通过有机材料，化石燃料，加工肉类，熏制食品的消耗以及各种工业活动的不完全燃烧释放出来。高分子量和高流动性使多环芳烃广泛传播，对人体健康具有致命性。人类的细胞系统通过称为异源生物代谢（CYP450）和II期（GSTs）酶（XME）的专门酶解作用对这些有毒物质进行排毒。这些代谢酶包括细胞色素P450家族（CYP1，CYP2），谷胱甘肽S转移酶和ALDHs。编码基因的XME中的基因多态性可能会破坏其代谢能力，使摄入的致癌物（PAHs等）解毒，这可能导致延长和增加摄入的有毒物质的暴露，并因此可能导致癌症。此外，PAHs可以通过改变XME的表观遗传标记来重新编程XME的基因功能，从而诱发癌症。这篇评论文章讨论了巴基斯坦XMEs基因中的个体基因多态性，其改变的表观遗传标记和暴露于PAHs之间的可能的相互作用，从而使巴基斯坦患上癌症。