Seeing Cancer with Color: Spectroscopic Imaging Platform Maps Tumor Landscape

by Christos Evangelou, MSc, PhD – Medical Writer and Editor

Cancer cells avoid detection by shielding themselves behind a complex molecular barricade of normal cells. This impenetrable tumor microenvironment hides cancer cells not only from the immune system but also from clinicians trying to diagnose and treat the disease.

A new imaging system that uses chromogenic molecular tags attached to antibodies to light up cancer cells is giving researchers an unprecedented view of the tumor microenvironment.1 Developed by scientists at Roche Diagnostics Solutions, this cutting-edge platform could unlock new ways to detect cancer cells within small tissue biopsy samples.

“This feasibility work established that brightfield multiplexing can be used to characterize the prostate tumor microenvironment, although future validation of the system on larger cohorts would be required before clinical implementation,” said Daniel R. Bauer, PhD, who is a scientist at Roche Pathology Research and Early Development and the corresponding author of this study.

The report was published in the Journal of Pathology Informatics.

 

Seeing Cancer in a New Light

Cancer detection and treatment remain challenging, with doctors often struggling to determine which patients will respond best to available therapies. Growing evidence suggests that the complex cellular and molecular environment of tumors plays a key role in how aggressive cancer cells are and whether they can evade therapies.

Standard diagnostic methods, such as hematoxylin and eosin (H&E) staining, provide only a limited perspective and reveal basic tissue morphology. Immunohistochemistry (IHC) assays allow the assessment of a limited number of protein biomarkers at a time, and attempting higher-order multiplexing with traditional stains creates overlapping dye colors that become indistinguishable.

To overcome this hurdle, a team of scientists at Roche developed a hybrid technique that harnesses the power of multiplex immunohistochemistry using novel spectroscopic imaging. This approach uses custom-designed chromogenic tags that attach to specific cell proteins.1

“To explore how compatible our brightfield multiplexing system is with hypothesis-free next-generation analytics, we used digital pathology and machine learning to analyze images derived from our hybrid chromogenic multiplexing system,” said Dr. Bauer.

He explained that the system harnesses the power of multiplex IHC but uses an unconventional approach with custom-engineered chromogens. When viewed under a specialized microscope, these chromogens selectively absorb light at different wavelengths. Computer algorithms then separate each chromogen signal into a virtual representation, where cell types “light up” based on the surface proteins they express. This approach enables simultaneous analysis of multiple cell markers within the tumor and the surrounding microenvironment.

“By integrating translucent detections with multispectral imaging hardware, deconvolution software, and open-source analysis algorithms, we developed a system that can characterize tumor and immune profiles, explore multivariate cellular features in a lower dimensionality space, and explore the spatial relationships between biomarkers pertinent to prostate cancer,” noted Dr. Bauer.

 

Proof of Concept

To evaluate the potential of their new imaging platform for mapping the cancer landscape, the researchers applied the technique to 143 prostate cancer tissue samples with varying stages of disease.1 They focused on six cell markers, including proteins found predominantly on prostate cancer cells, immune cells, proliferating cells, and prostate basal cells. These proteins target diverse aspects of the prostate tumor microenvironment, including prostate cancer biomarkers (PSMA and p504s), immune markers (CD8 and PD-L1), a prognostic marker (Ki-67), and diagnostic biomarkers (basal cell cocktail).

The platform yielded high-resolution images that captured diverse cell types within small tissue structures. When researchers quantified and compared cell marker levels between healthy tissue and prostate tumors, they found significant differences that correlated with the presence and severity of cancer, confirming the potential of the technique for detecting disease.1

“Readers should be aware that our technology is compatible with analytical methodologies that have traditionally been used with immunofluorescence-based multiplexing,” noted Dr. Bauer.

The team then analyzed the images using artificial intelligence to extract over 90 features related to cell type, number, staining patterns, and proximity between cells. When they condensed these high-dimensional data into just two components and applied cluster analysis, the algorithm could differentiate between healthy tissue and cancer with 89% accuracy.1 Moreover, the algorithm identified cell feature patterns corresponding to different cancer grades.

In addition, spatial analysis revealed that several protein-to-protein distances (especially involving p504s) were significantly closer in adenocarcinoma tissues than in healthy prostate tissues, offering insights into tumor development.

 

Future Work

This proof-of-concept study demonstrates that the new multiplex imaging platform can provide critical insights into cancer biology by illuminating the tumor landscape. Findings revealed intriguing spatial relationships between prostate cancer cells and surrounding immune and basal cells that may influence tumor survival and spread.

However, further validation of the platform in larger cohorts is required. The authors acknowledge that their analysis was performed at the tissue level, without distinguishing between normal glands, tumor cells, or stromal cells, which could affect the granularity and accuracy of the data.

“Future work for this project will be to take the tools that have been developed and apply them to a larger sample cohort. We would also like to refine the biomarkers to evaluate if better signatures can be elucidated,” said Dr. Bauer. He added that performing analysis based on compartmental regions from expert pathologist annotation of the tissue would provide additional insights.

Although validation in larger patient cohorts is required, the clinical potential of this technique is clear. Combining clinically applicable brightfield multiplexing with advanced analytics creates a powerful diagnostic platform to match patients with optimal therapies, with the potential to enable translation of spatial biology research into clinical practice. By condensing massive amounts of biological data down to simple visual outputs, the imaging system could equip pathologists with next-generation diagnostics to guide personalized cancer therapy. The future possibilities make this color revolution worth watching.

The study was funded by Roche Diagnostics Solutions.

 

References

  1. Rahul Rajendran, Rachel C Beck, Morteza M Waskasi, et al. Digital analysis of the prostate tumor microenvironment with high-order chromogenic multiplexing. J Pathol Inform. 2024;15:100352. doi:10.1016/j.jpi.2023.100352

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