Cancer-linked FAM190A Gene May Regulate Cell Division

Researchers from Johns Hopkins believe they may have discovered a little-described gene known as FAM190A that plays a subtle but critical role in normal cell division regulation process, known as mitosis. The study author's said they are hopeful that this information could help more clearly understand chromosomal instability in cancer.

Investigators studied these cells to find that knocking down expression of FAM190A disrupts mitosis. In fact, in three pancreatic cancer-cell lines, a standard human cell line engineered to be deficient in FAM190A, researchers observed that cells often had difficulty separating at the end of mitosis, creating cells with two or more nuclei.

"These cells try to divide, and it looks like they succeed, except they wind up with a strand that connects them," said Scott Kern, M.D., professor of oncology and pathology at Johns Hopkins University School of Medicine and its Kimmel Cancer Center, via a press release. "The next time they try to divide, all the nuclei come together, and they try to make four cells instead of two. Subsequently, they try to make eight cells, and so on." Movies of the process taken by Kern's laboratory are available on the journal Web site.

Kern's group looked at deletions involving the gene that could be found in nearly 40 percent of human cancers. In fact, alterations found in FAM190A messages may be the third most common in human cancers after more well known genes, such as p53 and p16, according to Kern.

"We don't think that a species can exist without FAM190, but we don't think severe defects in FAM190A readily survive among cancers," Kern said. "The mutations seen here are very special - they don't take out the whole gene but instead remove an internal portion and leave what we call the reading frame. We think we're finding a more subtle defect in human cancers, in which mitosis defects can occur episodically, and we propose it may happen in about 40 percent of human cancers."

Background information from the study shows us that abnormalities from FAM190A can cause chromosomal imbalances seen very commonly in cancers. Multipolar mitosis is one of the most common functional defects reported in human cancers, and more than 90 percent of humans have abnormal numbers of chromosomes.

More information regarding the study can be found in he American Journal of Pathology.