The traditional ASL sign for "cancer" is rather gruesome. Then again, cancer is a rather gruesome thing. The sign is based on the concept that cancer "eats away" at a person's body. Thus the dominant hand represents the cancer as it chews up the body.
CANCER:
Sample sentence: Does anyone in your family have cancer? [ANY YOUR FAMILY HAVE CANCER?] (.mp4 video embed)
CANCER-[arm-version] / flesh eating:
Notes: