New Research Raises Concerns About PI3K Mutation as A Drug Target in Breast Cancer

“A leading gene candidate that has been the target of breast cancer drug development may not be as promising as initially thought, according to research published in open access journal Genome Medicine.”Mutation in the gene PIK3CA is the second most prevalent gene mutation in breast cancer and is found in 20% of all breast cancers. This has led people to think these changes may be driving breast cancer. Yet these mutations are also known to be present in neoplastic lesions -pre-cancerous growths many of which are thought to be benign, that have not invaded the surrounding tissue.

“Researchers from Stanford University wanted to better understand these neoplastic growths and how they related to the carcinoma. They sequenced the genes from tissue taken from the breasts of six women who had undergone a mastectomy, leading to a total of 66 samples, which included 18 carcinomas and 34 neoplastic lesions.

“A specific mutation in the PIK3CA gene occurs in the same patient multiple times. This was found to be the case for four out of the six women. In two out of these four cases, this mutation occurs in the neoplastic lesions, which are not considered tumors, but does not occur in the invasive carcinoma.”

Myriad Adds to Clinical Utility Data Backing Use of Melanoma Dx to Discern Malignant, Benign Lesions

The gist: Doctors sometimes perform molecular testing on patients’ tumors to identify certain characteristics that can inform treatment decisions. This article describes a molecular test called myPath Melanoma. It helps doctors determine is a patient’s skin lesion is malignant melanoma or benign. Recent research showed that myPath Melanoma helped doctors change their treatment decisions. In particular, many doctors opted for less intensive treatments for their patients based on myPath results.

Myriad Genetics this week presented data showing that its multi-gene myPath Melanoma test helped doctors change their treatment decisions, often lowering the intensity of the treatment strategy, for 35 percent of nearly 700 cases of pigmented skin lesions.

“Myriad presented the data, from a second clinical utility study for myPath Melanoma, at the College of American Pathologists’ annual meeting this week. The results of the prospective analysis aligned with findings from a retrospective clinical utility study presented earlier this year, which showed that doctors changed their decisions for 33 percent of cases using myPath Melanoma results.

“Myriad is marketing the 23-gene panel test, list priced at $1,500, as a tool that doctors can use to determine if a patient’s skin lesion is malignant melanoma or benign. Late last year the company provided early access to the test to dermatopathologists in the US through ‘The melEval Program.’ The test, according to Myriad, is one that pathologists can use to arrive at a more definitive diagnosis for suspicious, difficult-to-assess skin lesions. To date, approximately 120 dermatopathologists have submitted samples for testing with myPath through the early access program, according to the firm.

“In the latest prospective clinical utility study, 42 dermatopathologists answered questions about their treatment decisions for 687 cases of pigmented skin lesions, before and after performing the myPath Melanoma test. Myriad researchers asked these doctors to document their level of confidence about their diagnosis (is the skin lesion benign, malignant, or indeterminate) and their treatment recommendations before and after the test was performed.”