This theory is further supported by a cross-sectional study which found elevated mean serum lipid peroxides in the As exposed individuals which correlated with blood levels of inorganic arsenic and methylated metabolites and inversely correlated with nonprotein sulfhydryl (NPSH) levels in whole blood. Another study found an association of As levels in whole blood with the level of reactive oxidants in plasma and an inverse relationship with plasma antioxidants. A finding of the latter study indicates that methylation might in fact be a detoxification pathway with regard to oxidative stress: the results showed that the lower the As methylation capacity was, the lower the level of plasma antioxidant capacity. As reviewed by Kitchin (2001), the oxidative stress theory provides an explanation for the preferred tumor sites connected with arsenic exposure. Considering that a high partial pressure of oxygen is present in lungs and DMA(III) is excreted in gaseous state via the lungs, this seems to be a plausible mechanism for special vulnerability. The fact that DMA is produced by methylation in the liver, excreted via the kidneys and later on stored in the bladder accounts for the other tumor localizations. Regarding DNA methylation, some studies suggest interaction of As with methyltransferases which leads to an inactivation of tumor suppressor genes through hypermethylation; others state that hypomethylation might occur due to a lack of SAM resulting in aberrant gene activation. An experiment by Zhong et al.
Persistent tunica vasculosa lentis is a congenital ocular anomaly. It is a form of persistent hyperplastic primary vitreous (PHPV). It is a developmental disorder of the vitreous. It is usually unilateral and first noticed in the neonatal period. It may be associated with microphthalmos, cataracts, and increased intraocular pressure. Elongated ciliary processes are visible through the dilated pupil. A USG B-scan confirms diagnosis in the presence of a cataract. See also
Persistent fetal vasculature
Tunica vasculosa lentis

References

http://www.djo.harvard.edu/files/1568.pdf
Wright KW, Speigel PH, Buckley EG. Pediatric Ophthalmology and Strabismus. Springer; US, New York: 2003. p. 17.