Optimising multiplexing immunofluorescence staining of tissue sections to study immune infiltration of the tumour microenvironment

Somerville, Michelle 2025. Optimising multiplexing immunofluorescence staining of tissue sections to study immune infiltration of the tumour microenvironment. PhD Thesis, Cardiff University. Item availability restricted.

	PDF (Thesis) - Accepted Post-Print Version Restricted to Repository staff only until 16 October 2026 due to copyright restrictions. Download (15MB)
	PDF (Cardiff University Electronic Publication Form) - Supplemental Material Restricted to Repository staff only Download (365kB)

Abstract

Spatial biology is transforming biomedical research by deepening our understanding of disease mechanisms, identifying novel therapeutic targets, and improving strategies for patient stratification. Cancerous tumours are not composed solely of malignant cells; they also include infiltrating immune cells, extracellular matrix components, and a variety of secreted factors. The composition and organisation of the tumour microenvironment play a critical role in shaping immune cell behaviour and can influence whether a tumour responds to therapy or develops resistance. To explore these complex interactions while preserving spatial architecture of tissue a novel multiplex staining technique was combined with innovations in microscope filter configurations for whole slide imaging (WSI) to study two cohorts of cancer samples. The relationship between improved outcomes in colorectal cancer and a higher degree of immune infiltrate has been well-documented. In this thesis mapping of immune infiltrate by multiplex staining of colorectal cancer (CRC) tissue samples revealed a previously unrecognised pattern of immune exclusion. This exclusion was linked to increased density of ZEB1 expressing cells in tumour-adjacent stroma. Levels of immune infiltration into tumour clusters correlated with tumoural major histocompatibility complex class II (MHC-II) expression but the same association was not true of MHC class I. Strikingly a subset of MSS tumours -which are typically considered immune-poor- showed high immune infiltration levels. These findings expand our understanding of the variation in immune phenotypes in CRC and lay a foundation for future studies. Immune checkpoint inhibition to boost anti-tumour immunity is an established treatment strategy. In this thesis expression of LAG3 and three of its ligands Galectin-3, FGL1 and MHC-II was examined in a cohort of triple negative breast cancer (TNBC) samples. LAG3 expression was observed in immune cells as expected but was also present in tumour cells. Tumoural LAG3 expression was often accompanied by FGL1. These observations support the need for further research into the implications of LAG3-FGL1 signalling in TNBC and its usefulness as a potential therapeutic target.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Medicine
Date of First Compliant Deposit:	16 October 2025
Last Modified:	16 Oct 2025 14:43
URI:	https://orca.cardiff.ac.uk/id/eprint/181719

Actions (repository staff only)

Edit Item