approached should be approach? A typo?

Context:

The remaining 10 percent use a mechanism known as ALT, short for alternative lengthening of telomeres. "Although it is a rare phenomenon, understanding ALT is essential since tumors can evade anti-cancer therapies aimed at inhibiting the activity of telomerase through the activation of ALT," explains postdoctoral researcher and first author Liana Oganesian, Ph.D. "This is why we clearly need a two-pronged approached to successfully tackle cancer."

More:
http://www.sciencedaily.com/releases/2011/04/110421122327.htm