Quantitative Analysis of the 3D Morphology and Immune Cell Interactions in Ductal Carcinoma In Situ

Abstract

Ductal Carcinoma In Situ (DCIS) is the most common preinvasive finding in mammographic screening and a non-obligate precursor to invasive breast cancer, but the mechanisms underlying its transition to invasive breast cancer remain unclear. One proposed mechanism resulting in a more invasive disease is neoductgenesis, a morphological feature present in a subset of DCIS cases characterized by the development of distorted duct-like structures. While some evidence supporting the origin and mechanisms of neoductgenesis has been published, more extensive research is crucial for understanding this phenomenon and translating findings into clinical diagnostics and care. In this project, 3D reconstruction histology, multiplex immunofluorescence, and quantitative image analyses were employed to analyse the 3D morphology, preferential immune cell accumulation and macrophage subtypes of DCIS. Analyses revealed a group of tumour areas consisting of thin tumour segments growing out of larger branches, which corresponded to previously described criteria and clinical features of neoductgenesis. Interestingly, immune cells were observed to preferentially accumulate around thin tumour segments in 3D. Multiplex immunofluorescence analysis of macrophage subtype markers in tissue sections revealed that immune cell clusters are more populated by tumour-associated macrophages in DCIS with neoductgenesis compared to standard presentation of DCIS. In all, our evidence suggests that neoductgenesis is a morphologically distinct 3D histological feature that could be associated with a tumour promoting microenvironment. In the future, similar studies must be conducted on larger patient cohorts to validate these findings and to, eventually, bring new diagnostic tools into clinical practice.