By Kirell Lakhman

KISSIMMEE, Fla. ― The vast majority of attendees of a session at this year’s annual Association for Molecular Pathology meeting said they use Vysis’ FISH assay when assessing Her2 status, according to an informal poll that offered three other options.

To be sure, the session, jointly led by Greg Tsongalis, director of Dartmouth's Hitchcock Medical Center's molecular pathology lab, and William Highsmith, director of Laboratory Medicine and Pathology at the Mayo Clinic in Rochester, Minn., was not meant to compare how clinical labs use FISH or other molecular technologies.

Rather, it was meant to describe in detail a handful of errors ― most small, some potentially life-altering ― that occurred in their labs, under their watch, and asked attendees to vote on a set list of possible steps that would have prevented them.

One case study polled the 200 or so attendees which platform they use when assessing Her2 status. The presenters offered four options: the PathVysion FISH assay made by Vysis, a unit of Abbott Molecular; Ventana’s INFORM assay (Ventana is a Roche business); quantitative real-time PCR; and “other” lab-developed tests.

The results showed that 80 percent of respondents use the PathVysion; 8 percent use the INFORM assay; 8 percent employ quantitative real-time PCR; and 4 percent rely on “other” lab-developed tests.

Physicians prescribe Her2 tests to help them determine if a woman with breast cancer should undergo therapy with Herceptin. The two top players in the Her2 market are currently Dako, which sells the IHC-based HercepTest, and Vysis. Both tests are approved by the FDA.

What was interesting to me was that the unscientific poll (participants discreetly punched in their responses on a handheld device) happened to coincide with a symposium, also presented at AMP, arguing that FISH should be the technology of choice when measuring the amplification of the Her2 gene in human breast cancer tissue specimens.

Presenting at the symposium was Michael Press, a pathologist at the University of Southern California’s Norris Comprehensive Cancer Center. “An issue with FISH for Her2 testing is that up to 2 percent of breast cancers have FISH ratios at or near the cutoff level,” Press was quoted as saying in a statement released by Abbott today. “However, we are aware of no published data demonstrating that patients with borderline Her2 amplification respond less favorably” to Herceptin.

Press’ talk, which was sponsored by Abbott, was based on results of a study he co-authored that appeared in the Journal of Clinical Oncology earlier this year. The study “refut[ed] guidelines developed by the American Society of Clinical Oncology and the College of American Pathologists that recommended immunohistochemistry as the preferred diagnostic method for determining a breast-cancer patient’s Her2 status,” according to Abbott.

According to Abbott, FISH technology is an accurate, reproducible and predictive diagnostic method for testing women with breast cancer who are candidates for drug treatments targeted to the Her2 tumor receptor.”

“The debate on how to select patients who will respond best to costly drug treatments for aggressive breast cancer now favors FISH to measure the Her2 receptor found in human breast tumors,” the company said.