In checklists, new approach for predictive markers

“We’re taking advantage of something that was already on the books,” Dr. Bellizzi adds, “and using it to its best generalized purpose. We took an excellent checklist requirement that specifically referred to validation and verification of HER2. Then, instead of alternatively adding a PD-L1 validation checklist requirement, and a BRAF checklist requirement, et cetera, we used this as a tool to help labs best validate and verify their new predictive markers, and as a tool to help laboratory inspectors inspect labs on the validations and verifications of new predictive markers. Because this requirement had been worked out so proficiently for its original purpose, it seemed smart to call it into action for everything else.”

The requirement’s note says test verification of FDA-cleared or -approved assays must be performed on a minimum number of 40 cases and that labs should consider using higher numbers of cases when validating laboratory-developed tests. For HER2 and ER/PR predictive marker testing performed on breast cancer specimens using LDTs, 40 positive and 40 negative samples must be used at a minimum.

• MOL.39315/CYG.47885 Annual Result Comparison—Breast Carcinoma. This new requirement, based on ANP.22970, calls for the lab to compare at least annually its patient results for ISH tests performed on breast carcinoma with published benchmarks and evaluate interobserver variability among those performing the technical component.

Laboratories that perform ISH should know their annual rate of ISH positivity in their breast cancer cases, Dr. Bellizzi says. “Is it 10 percent? Is it 90 percent? If it’s some number that’s way off from what would be expected, then it’s a tool for laboratories to suspect that their assay might be performing suboptimally.” This requirement serves two purposes. “It has to do with how the assay is doing globally, and it is also one of the only tools we have to assess how individuals are doing reading the assay,” Dr. Bellizzi says, adding that it also compares the performance of individual pathologists who read the assay. “This is totally new for the cytogenetics and molecular checklists. Labs need to know about it because they need to establish internally a new policy and procedure to satisfy this requirement. And they have to compile their data and be able to spit it out.”

• MOL.39365/CYG.48950 Predictive Marker Testing—Decalcified Specimens. This is a new requirement for the validation and reporting of results from decalcified specimens and is based on ANP.22985. “Basically this says that decalcification needs to be taken into account when validating an assay and in reporting an assay,” Dr. Bellizzi says.

• GEN.40125 Handling of Referred Specimens; ANP.22983 Fixation—HER2 and ER/PgR Breast Cancer Predictive Marker Testing; and MOL.39358/CYG.48932 Fixation—HER2 (ERBB2) Breast Predictive Marker Testing. GEN. 40125 describes the specimen handling responsibilities of laboratories that refer specimens to other laboratories. “A main change, specifically referring to breast tissue here, is that for pathology specimens, the cold ischemia time and total fixation time must be recorded and submitted to the referral laboratory,” Dr. Bellizzi explains. “It is the responsibility of the lab referring out to provide it, and the responsibility of the reference lab to ask for it. These checklist requirements work in tandem to say, ‘You’re both responsible for this important parameter.’”

In general, Dr. Bellizzi says, revisions will provide clarity that may have been lacking previously. “Because of the way checklist requirements were structured before, with many that applied specifically to breast predictive biomarkers but not to others, it almost seemed as if there were two different standards for predictive markers. These revisions make clear that, for certain aspects, all predictive markers should be held to the same standard.”

Until fairly recently, Dr. Nakhleh says, there were so few predictive markers in use that writing new checklist requirements for them was manageable. But the number of emerging markers now demands a more universal approach to checklist requirements, which the 2019 checklist edition provides, he says.

The highest hurdle, Dr. Bellizzi says, was getting all team members to think broadly across the disciplines and understand how the changes might affect the laboratory as a whole. “As pathologists we tend to be in silos, operating in these huge, complex interconnected systems, but doing work that’s fairly specific. For this project we had to work together, think more broadly than any of us were accustomed.”

The new and revised requirements will help laboratories that implement new predictive marker testing, Dr. Goodman says. “They will help them ensure they’re doing testing properly, appropriate validation and verification studies, appropriate proficiency testing, and that the specimens are undergoing appropriate preanalytic handling.”

Dr. Goldsmith agrees, calling the checklists “the 10 commandments of running a laboratory.”

“Revised and improved checklists help those in laboratory medicine understand why predictive markers are different from nonpredictive markers and how to treat them differently. The revisions are instructive and ensure quality. In the end,” he says, “all of it serves patients and improves outcomes.”

And that, Dr. Nakhleh adds, “serves our membership as well.”

Valerie Neff Newitt is a writer in Audubon, Pa.