The cost of sequencing a human genome has come down, way down; and the value of doing it is going up. Here’s a very good example: scientists at the University of California Los Angeles (USA) recently completed the sequencing of the DNA from a type of brain cancer cell line, a glioblastoma known as U87. While the initial human genome study cost a billion dollars and took years, this genome analysis was done in one month at the cost of $35,000. In the field of neuro-oncology, that’s not even the cost of a single brain operation.
The particular form of brain cancer was chosen because it is one of the most studied. More than a thousand labs worldwide have been working on glioblastoma (often abbreviated as GBM), as it is relatively common, and usually fatal. Having the complete DNA sequence at hand puts doctors in a position to compare against patient gene sequences, which could be the beginning of personalized treatment for this type of cancer. Doctors and researchers can use a website specifically created to share the genome information, and it is hoped that research groups will be able to re-examine some of their findings in light of more complete information on the genes affected by GBM.
“This is very exciting because we, as scientists, can now move forward with revealing complete cancer genomes,” said Nelson, who directs the cancer center’s Gene Expression Shared Resource. “Cancer is at its heart a genetic disease. Cancer cells have acquired mutations that allow them to invade tissues and to not live by the normal rules. The changes from normal (mutations) that have given the cancer these special properties are encoded in DNA, and the entire DNA sequence has just been to complex and costly to decode until now.”
“Sometimes it’s difficult to tell if a cancer is coming back or if what you’re seeing is scar tissue,” Nelson said. “Scientists could develop a sensitive molecular assay that looks for a unique mutation found only in the cancer cells and not in the healthy cells. If that mutation is found by the assay, the cancer has returned and patients could be promptly treated when the recurrence is at its earliest stage and easiest to treat. Conversely, such an assay could be used to determine when the cancer has been effectively eliminated and it’s safe to discontinue what are harmful treatments.”