Potential role of M2 TAMs around lymphatic vessels during lymphatic invasion in papillary thyroid carcinoma

Takanobu Kabasawa,Naing Ye Aung,Takumi Kitaoka,Yuka Urano,Rintaro Ohe,Nobuyuki Tamazawa,Mitsunori Yamakawa,Aya Utsunomiya

doi:10.1038/s41598-020-80694-3

Takanobu Kabasawa, Naing Ye Aung + Show 6 more

Open Access

https://doi.org/10.1038/s41598-020-80694-3

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Journal: Scientific Reports	Publication Date: Jan 13, 2021
Citations: 9	License type: open-access

Affiliation: Yamagata University

Abstract

The aim of this study was to examine whether lymphatic invasion in papillary thyroid carcinoma (PTC) occurs when tumour-associated macrophages (TAMs) injure lymphatic vessels together with cancer cells. While there was no difference in the lymphatic vessel density in PTC and follicular thyroid carcinoma (FTC), the number of TAMs around the lymphatic vessels was increased in PTC compared to that in FTC. In particular, TAMs were observed together with cancer cells in lymphatic invasive lesions, and the number of M2 cells inside and outside the lymphatic vessels showed a significant correlation. MMP-2 mRNA was expressed in nonneoplastic stromal cells as well as cancer cells, and double immunofluorescence staining confirmed M2 positivity. Consequently, this study reveals that M2 TAMs around lymphatic vessels within the tumour border of PTC may be associated with the lymphatic invasion of cancer cells. This study represents a step forward in elucidating the mechanism of lymphatic invasion.

Highlights

MMP-9 play important roles in cancer infiltration[13]
This study revealed for the first time in tissue sections that M2 TAMs around the lymphatic vessels within the tumour border of Papillary thyroid carcinoma (PTC) may be associated with the lymphatic invasion of cancer cells
We initially examined the density of lymphatic vessels around the tumour border as a cause of frequent lymph node metastasis in PTC

Summary

Introduction

MMP-9 play important roles in cancer infiltration[13]. It is unclear whether TAMs are involved in the lymphatic invasion of thyroid cancer cells. We hypothesized that "lymphatic invasion in PTC occurs because TAMs injure the lymphatic vessels together with cancer cells". This study revealed for the first time in tissue sections that M2 TAMs around the lymphatic vessels within the tumour border of PTC may be associated with the lymphatic invasion of cancer cells

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