Technique Maps Biomarkers That Predict Immunotherapy Response

With only 1 slide of a tumor section, an analysis of multiple tumor markers can be performed. This new technique may help identify which patients will respond to immunotherapy, which typically evokes responses in only a small group of patients.¹

The technique characterizes human cells involved in immune responses at the tissue site before and after treatment with immunotherapy. It is called multiplexed immunohistochemical consecutive staining on a single slide (MICSSS). Researchers hope the technique helps to define new biomarkers that predict patient outcomes.

Improved outcomes for patients with various forms of cancer are associated with a measurable immune response at the tumor site. However, a lack of methods to characterize the complex relationships between immune cells and cancer cells and the difficulty of obtaining enough tissue to do so with standard methods hampers the ability to study the mechanisms at play.

“Our goal was to get a better understanding of immunologic responses at the tumor site while addressing the need for high-dimensional analysis using as little tissue as possible,” said senior author Sacha Gnjatic, PhD, associate professor of immunology, hematology, and medical oncology at the Tisch Cancer Institute (TCI) at the Icahn School of Medicine at Mount Sinai, New York, New York. “We need more comprehensive analyses of the immune microenvironment of tumors, as part of our immune monitoring to inform treatment and predict outcomes for cancer patients.”

The MICSSS technique was applied to tumor tissue sections of melanoma and lung cancers. The researchers were able to view co-expression of markers on the same cells while sparing material from tissues.

“The MICSSS technique helps us characterize the distribution of complex cell subsets in tumor tissues without cross-reactivity between staining cycles,” explained Romain Remark, PhD, a postdoctoral fellow at TCI. “In contrast to other available methods, our approach is not as reliant on proprietary reagents or instruments and should be easier to adapt because it follows the same staining steps currently implemented throughout all pathology labs.”

Next, MICSSS will be tested for mapping other tumor types, such as hepatocellular carcinoma and colorectal, breast, head and neck, or pancreatic cancers. If successful, the researchers believe the technique may be useful beyond cancer, as it offers the ability to reuse any slide from a tissue sample up to 10 times and characterizes multiple parameters with standard chromogen staining. MICSSS is being applied to characterizing immune and tissue markers of diabetes, HIV-related kidney pathology, inflammatory bowel disease, and atherosclerosis.

The researchers hope to implement MICSSS as part of the Human Immune Monitoring Center at TCI to characterize the types of immune cells infiltrating various cancers and other disease for their density, localization in the tissue, and diversity.

Reference

1. Remark R, Merghoub T, Grabe N, et al. In-depth tissue profiling using multiplexed immunohistochemical consecutive staining on single slide. Science Immunology. 2016 Jul 14. doi:10.1126/sciimmunol.aaf6925. [Epub ahead of print]