Arsenic (As), cadmium (Cd), chromium (Cr), and nickel (Ni) are category 1 heavy metals according to the International agency for Research on Cancer. Various reports, including this one, have found that exposure to these compounds leads to disruptions in tumor suppressor gene expression, damage repair processes, and enzymatic activities concerned in metabolism via oxidative damage
Cadmium and its compounds are highly toxic and exposure is known to cause cancer. It is primarily associated with human lung, prostate, and kidney cancers, and recently pancreatic cancer. It has also been associated with cancers of the breast and urinary bladder.