In multiple papers published today in Science, researchers from the Broad Institute, the Dana-Farber Cancer Institute, Johns Hopkins Kimmel Cancer Center, the University of Pittsburgh, and the University of Texas MD Anderson Cancer Center confirmed the theory that certain genetic mutations — including of the tumor suppressor gene p53 — play a part in head and neck cancer. According to a press release from the groups involved, the two teams have also found mutations in the NOTCH gene family that may play a role in how the cancer is developed. The NOTCH genes usually control how cells differentiate, mature, stop dividing, and die — the implication from these two studies is that this function may be somehow impaired in head and neck cancer, the press release says. One team collected 74 pairs of normal and cancerous tissue and performed whole-exome sequencing, while the other team studied the whole exomes of 32 pairs of tumor and normal tissue samples and validated their findings in an further 88 samples. Both teams found mutations in p53 in more than half the tumors they studied, the press release says. The teams also found mutations in NOTCH1 in about 15 percent of the tumors. "In head and neck cancer, the scientists saw mutations that turn NOTCH1 off, blocking differentiation and trapping cells in a proliferative, pro-cancer state. Their maturation is arrested, leaving them stuck in an earlier stage, where other damage from smoking or alcohol or even p53 mutations can destabilize the genome," the press release adds. "NOTCH1's inactivation in head and neck cancer was surprising because in other cancers, such as leukemia, too much NOTCH signaling leads to cancer." Both teams say that the next step is to find out how the genes function in normal cells when they form the lining of the larynx or other sites affected by head and neck cancers. Both teams also confirmed the role of human papillomavirus infection in the formation of head and neck cancers, the press release says, and that HPV-positive tumors contain fewer mutations than HPV-negative tumors.
Something Old … Something New
Jul 28, 2011