Both cancer types demonstrate a high frequency
of microsatellite instability, where the repair mechanism for DNA is broken, and mutations in POLE, a gene responsible for producing a protein involved in DNA replication and repair.
Not exact matches
The population - based study
of 503 people with colon cancer found that 14 percent
of Caucasians and 7 percent
of African - Americans had a genetic marker called
microsatellite instability, or MSI.
In 2017, the U.S. Food and Drug Administration (FDA) approved the cancer drug Keytruda (pembrolizumab) for a range
of solid tumors that are either
microsatellite instability - high (MSI - H) or mismatch repair deficient (dMMR).
Both development
of CRC and
microsatellite instability (MSI) are associated with chronic inflammation.
But a caveat is that many patients have few if any T - cells in their tumors, which means the treatment is effective in only about 20 percent
of patients who also have high
microsatellite instability.
In fact, the Food and Drug Administration's approval
of pembrolizumab in May 2017 for adult and pediatric patients with solid tumors and high
microsatellite instability, was the first time it had approved a cancer treatment based on a genetic feature rather than the cancer's location
of origin.
The primary tumor location was an independent prognostic marker in patients with RAS wild - type metastatic colorectal cancer after adjusting for age, gender, synchronous / metachronous disease, consensus molecular subtype, and
microsatellite instability and molecular status, according to the results
of an analysis (abstract 3503)
of data from CALGB / SWOG 80405 presented at the 2017 American Society
of Clinical Oncology (ASCO) Annual Meeting.
CHFR silencing or
microsatellite instability is associated with increased antitumor activity
of docetaxel or gemcitabine in colorectal cancer.
For the remaining 14 samples, a match was nearly perfect, with only one or two
of the
microsatellite markers varying, typically by only one repeat unit, as might be expected through
microsatellite instability within a pedigree.
Expression
of the MAP kinase phosphatase DUSP4 is associated with
microsatellite instability in colorectal cancer (CRC) and causes increased cell proliferation.