Arsenic helps tumors, blood vessels grow

In a blow against oncologists’ hopes that arsenic might serve as a versatile antitumor agent, researchers have found that the 33rd element of the periodic table may actually speed the growth of tumors.

High doses of arsenic are toxic to the heart, but lesser amounts have been shown to work therapeutically against leukemia. Some researchers therefore have considered periodic arsenic infusions for treating other forms of cancer.