Choosing controls

MANASSAS, Va.—The use of well-defined controls in assay development is essential for determining the reliability and reproducibility of data obtained from molecular applications. ATCC, which claims to have the world’s largest and most diverse collection of human, animal and plant cell lines, molecular genomic tools, microorganisms and biological products, spoke out on this topic during its first participation at the Corporate Workshop Day at the Association for Molecular Pathology (AMP) 2013 Annual Meeting, emphasizing the importance of using authenticated and highly characterized biomaterials for assay development and verification.

More than 75 researchers from pharmaceutical and molecular diagnostics companies attended the workshop. The presentation was divided into two parts, first focusing on controls for genetic mutations in cancer biology, followed by a discussion on the detailed characterization of ATCC infectious disease strains and nucleic acid controls.

Liz Kerrigan, director of standards at ATCC explains, “Next-generation sequencing has led to the genomic age, and the cost of sequencing the genome is falling. Large-scale sequencing programs are looking at mutations and target drugs and seeing the resistance.”

Kerrigan describes the challenges in molecular diagnostics as ‘omics data storage, data analysis, clinical quality standards for each step from sample to answer and appropriate and reliable controls. Although more than 1,900 genetic tests are available, the majority of tests still need characterized references or quality-control materials, she said.

Kerrigan explains that the need for molecular-based tests has increased significantly in the last few years, stimulated by the discovery of new hereditary genetic disease loci (biomarkers) following the completion of the Human Genome Project and by “the presence of emerging and reemerging microbial threats such as SARS, H1N1 and multidrug-resistant organisms such as TB.” She added that molecular assays provide several advantages, including increased specificity, sensitivity, rapid detection and identification of outbreaks, and can be used in oncology, infectious disease and genetic testing.

“As nucleic acids become major targets for analysis in clinical laboratories, the need for standardization is critical,” Kerrigan says. “Standards are needed to establish sensitivity, linearity and specificity during assay validation or implementation, quality assurance, quality control and proficiency testing.”

Kerrigan adds that standards are meant to improve reproducibility. The incorporation of standardized biological materials generates meaningful data that can be compared within or to other laboratories around the world. “Efficiency, reliability and reproducibility are critical factors when funding and resources are limited,” she says, adding that the development of biological standards for molecular testing promotes assay development, automation and third-party reimbursement for clinical testing.

“There are a lot of choices for controls in research, but it’s imperative to obtain controls from a reliable source; knowing how they were produced and how identities were verified,” Kerrigan insists. “That’s the importance of authentication.”

She went on to describe how ATCC maintains a rigorous quality-control program under ISO/IEC 17025, ensuring the identity and purity of biological materials. Cultures housed within the ATCC repository are managed under a seed stock banking concept, which limits passage and allows for strict quality-control testing to be performed on both seed and distribution materials. In addition to providing supplementary testing for tumor cell lines, ATCC also performs extensive analyses on geographically diverse infectious disease isolates to determine serotype, toxinotype and multidrug-resistance profiles.

As the tools available to laboratories change, ATCC is adapting to make it easier for investigators to locate genetic and phenotypic data related to the controls they need to challenge assay design and verify results. ATCC offers a growing list of tumor cell panels, genetic alteration panels, infectious disease and multidrug-resistant strains, synthetic and native nucleic acids and certified reference materials (CRM)—including the newest KRAS-mutation CRMs—for assay development, inclusivity/exclusivity testing and limits of detection.

Kerrigan concludes that next-generation sequencing is revolutionizing medical research and has the potential to be a powerful diagnostic tool for cancer. She says that challenges still remain, including areas of technical, computational, data interoperation, standards and certified reference materials. She believes that “authenticated cell lines and validated genetic alteration cell panels could be useful tools and controls in molecular diagnostic testing.”