title: The expression of tumor-associated macrophages in papillary thyroid carcinoma.
abstract: BACKGROUND
  Tumor-associated macrophages (TAMs) play a tumorigenic role related to advanced staging and poor prognosis in many human cancers including thyroid cancers. Yet, a functional role of TAMs in papillary thyroid carcinoma (PTC) has not been established. The aim of this study was to investigate TAM expression in human PTC with lymph node (LN) metastasis.
  
  
  METHODS
  Thirty-six patients who underwent surgery after being diagnosed with PTC with LN metastasis were included. Primary tumor tissues were immunohistochemically stained with an anti-CD68 antibody and clinical characteristics according to TAM density were evaluated.
  
  
  RESULTS
  The TAM densities (CD68(+) cells) varied from 5% to 70%, in all tumor areas, while few cells were stained in adjacent normal tissues. TAMs were identified as CD68(+) cells with thin, elongated cytoplasmic extensions that formed a canopy structure over tumor cells. Comparing clinicopathologic characteristics between tumors with low (<25%) and high (25% to 70%) TAM densities, primary tumors were larger in the high density group than in the low density group (2.0±0.1 vs. 1.5±0.1; P=0.009).
  
  
  CONCLUSIONS
  TAMs were identified in primary PTC tumors with LN metastasis and higher TAM densities were related to larger tumor sizes, suggesting a tumorigenic role of TAMs in human PTCs.
authors.affiliation: Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Seunghwan
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Department of Internal Medicine, National Medical Center, Seoul, Korea.
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Cho
authors.affiliation: Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hye Sook
authors.initials: HS
authors.lastname: Min
authors.affiliation: Hansung Science High School, Seoul, Korea.
authors.forename: Kang Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Biomedical Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Gye Jeong
authors.initials: GJ
authors.lastname: Yeom
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. ; Department of Surgery, National Medical Center, Seoul, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyu Eun
authors.initials: KE
authors.lastname: Lee
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. ; Department of Surgery, National Medical Center, Seoul, Korea.
authors.forename: Yeo Gyu
authors.initials: YG
authors.lastname: Yun
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
keywords: Thyroid cancer, papillary; Tumor size; Tumor-associated macrophages