Came across this new method of immunohistochemistry called multiplexed ion beam imaging, which allows for a greater number of simultaneous stains on one sample. Great for being able to understand the complex nature of tumors, and has the bonus of producing some spectacular images.

Image by Michael Angelo (no, I am not making that up) of a human breast tumor featured at the NIH Director's Blog. Picture description:

The location and abundance of six proteins—e-cadherin (green), vimentin (blue), actin (red), estrogen receptor, progesterone receptor, and Ki67—found in breast cancer cells are seen in this multiplexed ion beam image. Cells positive for estrogen receptor a, progesterone receptor, and Ki-67 appear yellow; cells expressing estrogen receptor a and the progesterone receptor appear aqua.

Images from a different multiplexing technique (it's a proprietary service from GE), but that I still thought were striking:

If you're interested in how the first image was achieved, this figure from their paper shows a nice summary.