Earwax comes in two varieties, and both are equally disgusting. Some people sport a wet, yellow-brown goo, while others have dry, grayish crumbs.
Interestingly, earwax type seems to be based on ethnicity. Most people from Europe and Africa have wet earwax, most people from East Asia have dry earwax, and people from Central and Southern Asia could have either type. This trend led scientists to think that earwax type could be determined by your DNA.
A few years ago, scientists found the genetic difference that determines what type of earwax you have. It's a matter of one tiny nucleotide. At a certain spot in your DNA, you either have a G (guanine nucleotide) or an A (adenine nucleotide). If you have an A at the spot on both of your chromosomes, you will have dry earwax. If you have a G on both chromosomes or an A on one chromosome and a G on the other, you will have wet earwax.
The gene where this difference occurs is used to make a specific transport protein. Then a certain type of gland in the body uses the transport protein to secrete gross substances, like earwax.
This gland isn't just found in the ear, however, it's also found in breast tissue. In fact, the transport protein in question was first discovered because there is an unusually large amount of it in cancerous breast tissue.
What's more, one researcher noticed that there were fewer incidences of breast cancer among populations of women with dry earwax. He even found that Japanese women who had breast cancer were slightly more likely to have wet earwax than Japanese women without breast cancer. In 2010, another group studied the earwax-breast cancer correlation at the gene level. As you might expect, they found a higher incidence of the wet earwax variation of the gene in Japanese women with breast cancer.
It seems, however, that the possible link between wet earwax and breast cancer risk might not hold for Caucasian women. One study published last year compared the earwax genes of 1,342 women with breast cancer and 2,256 women without breast cancer. The researchers found that the prevalence of the two earwax gene variations was the same in both groups of Caucasian women. Another 2011 study had similar results.
While it's exciting (albeit revolting) that earwax type could useful for catching breast cancer, it seems that there are still reasons to be skeptical of the correlation. But even if earwax can't be used as a diagnostic tool, it still has important uses for your body. It keeps your ears clean and free from intruders, and it lubricates the ear canal.