Breast cancer (BC) is a major threat to women's health because of its high incidence of metastasis and death [1]. The metastatic potential, recurrence rates, and treatment resistance of BC are significantly influenced by the tumor microenvironment (TME). Particularly, the presence of cancer-associated fibroblasts (CAF) in the TME are related to a poor prognosis. CAF can alter the TME through a variety of mechanisms including the production of cytokines, metalloproteinases (MMPs) and inhibitors of the Matrix Metalloproteinases (TIMPs). Moreover, variations in the expression of MMPs and TIMPs may contribute to the development of BC [2]. In fact, the production of TIMP-2 by CAF has been found to be a metastasis biomarker [3]. Moreover, CAF considerably impact the response to treatment in BC. This explains the importance of the study of the TME, distinguishing between the tumor niche and the stroma, which is formed by the extracellular matrix and non-tumoral cells like CAF.

The aim of this work was the development of a multiplex immunohistochemistry (IHC) assay in combination with LA-ICP-ToF-MS to investigate the role of CAF and TIMP-2 in BC development and metastasis. Two different lanthanides, Nd and Eu, were bioconjugated to the specific antibodies enabling quantitative bioimaging of both CAF and TIMP-2 in the tumor niche and stroma areas from metastatic and non-metastatic breast tissues. The results showed a significant overexpression of TIMP-2 by CAF in both the stroma (p=0.012) and tumor niche (p=0.008) of metastatic samples by the decrease of CAF/TIMP-2 ratio. Specifically, the ratio CAF/TIMP-2 in the stroma was 0.59 (0.46 – 0.84) for non-metastatic and 0.33 (0.26 – 0.38) for metastatic meanwhile in the tumor niche, they were 0.56 (0.43 – 0.75) for non-metastatic and 0.34 (0.27 – 0.38) for metastatic samples. The results show the importance of spatial analysis of the TME by LA-ICP-ToF-MS.

References

[1] Z. He; Cell Proliferation, 2020, 53, e12822.

[2] Y. Jiang; Oncogene, 2002, 21, 2245-2252.

[3] N. Eiró; Oncoimmunology, 2015, 4, 1-11.