Novel quantitative signature of tumor stromal architecture: polarized light imaging differentiates between myxoid and sclerotic human breast cancer stroma

Abstract

As a leading cause of death in women, breast cancer is a global health concern for which personalized therapy remains largely unrealized, resulting in over- or under-treatment. Recently, tumor stroma has been shown to carry important prognostic information, both in its relative abundance and morphology, but its current assessment methods are few and suboptimal. Herein, we present a novel stromal architecture signature (SAS) methodology based on polarized light imaging that quantifies patterns of tumor connective tissue. We demonstrate its ability to differentiate between myxoid and sclerotic stroma, two pathology-derived categories associated with significantly different patient outcomes. The results demonstrate a 97% sensitivity and 88% specificity for myxoid stroma identification in a pilot study of 102 regions of interest from human invasive ductal carcinoma breast cancer surgical specimens (20 patients). Additionally, the SAS numerical score is indicative of the wide range of stromal characteristics within these binary classes and highlights ambiguous mixed-morphology regions prone to misclassification. The enabling polarized light microscopy technique is inexpensive, fast, fully automatable, applicable to fresh or embedded tissue without the need for staining and thus potentially translatable into research and/or clinical settings. The SAS metric yields quantifiable and objective stromal characterization with promise for prognosis in many types of cancers beyond breast carcinoma, enabling researchers and clinicians to further investigate the emerging and important role of stromal architectural patterns in solid tumors.

Peri‐tumoural stroma collagen organization of invasive ductal carcinoma assessed by polarized light microscopy differs between OncotypeDX risk group

“…Imaging was done using the previously described polarimetric microscopy setup and methodology. [ 25, 26 ] Polarized light microscopy (PLM) is a well‐established approach for enhancing the contrast of birefringent materials such as collagen. An AxioZoom V16 microscope (Zeiss, Germany) was fitted with two linear polarizers (Thorlabs, LPVISE100‐A) and controlled with motorized rotation mounts (PRM1.MZ8, Thorlabs, New Jersey).…”

“…Imaging was done using the previously described polarimetric microscopy setup and methodology. [25,26] Polarized F I G U R E 1 Sample annotation and imaging process. A, H&E stained IDC surgical samples were imaged at ×20 and tumor ROIs were contoured (purple region).…”

“…Two metrics, namely abundance and alignment, were extracted from the polarimetric images for each sample. Both were previously used by our group to assess collagenous stroma in breast cancer, [25,26] and each examines a distinct feature.…”

“…[20,24] Previous efforts by our group have demonstrated the potential of a novel form of polarimetric imaging to analyze the organization of collagenous stroma in breast cancer samples. [25,26] For example, we have used this polarized light imaging approach to develop a quantitative stromal architecture signature (SAS) score capable of differentiating myxoid from sclerotic stroma within the TME. Herein we extend this approach to examine the correlation of polarimetrically derived collagen morphology metrics with OncotypeDX risk groups.…”

Polarimetric biomarkers of peri-tumoral stroma can correlate with 5-year survival in patients with left-sided colorectal cancer

“…We have recently developed a simple and information-rich polarized light microscopy approach to characterize tumour stromal morphology. Technologically simpler than the Mueller matrix approaches, this methodology has enabled quantitative assessment of stromal maturity and the tumour-stroma ratio in breast cancer tissue samples; comparison against pathologist classifications yielded excellent initial agreement 34 , 35 . Another investigation correlated polarimetrically-derived stromal metrics with genetic prognostication results (OncoTypeDX), also with good agreements 36 .…”