Wow!  So today NASA announced that it has found a whole new branch of life that uses arsenic in place of phosphorus in its chemical makeup.

The newly discovered microbe, strain GFAJ-1, is a member of a common group of bacteria, the Gammaproteobacteria. In the laboratory, the researchers successfully grew microbes from the lake on a diet that was very lean on phosphorus, but included generous helpings of arsenic. When researchers removed the phosphorus and replaced it with arsenic the microbes continued to grow. Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new GFAJ-1 cells.
Source: NASA

There’s also an article about this on The Star.

The discovery “does show that in other planetary environments organisms might be able to use other elements to drive biochemistry and that the ‘standard’ set of elements we think are absolutely necessary for life might not be so fixed,” commented Charles Cockell
Source: The Star

Goes to show you, we can’t be so narrow minded when searching for life on other celestial bodies.