The clinicopathological significance of angiogenesis in hindgut neuroendocrine tumors obtained via an endoscopic procedure.
BACKGROUND
As the World Health Organization grading system for gastroenteropancreatic-neuroendocrine tumors (GEP-NETs) may not always correlate with tumor progression, it is imperative that other independent predictors of tumor progression be established. To identify such predictors, we conducted a retrospective histopathological study of hindgut NETs, obtained from endoscopic procedures, and used statistical analyses to evaluate predictive factors.


METHODS
We first obtained clinicopathological data of cases of hindgut NETs. Tissue sections from tumor samples were prepared and subjected to pathological examination. In particular, we calculated the microvessel density (MVD) and lymphatic microvessel density (LMVD) values, and performed appropriate statistical analyses.


RESULTS
A total of 42 cases of hindgut NETs were selected for the study, 41 from the rectum and 1 from the sigmoid colon. Based on the Ki-67 labeling index, 34 cases were classified as NET G1 tumors and 8 as NET G2 tumors. MVD values ranged from 1.4/mm2to 73.9/mm2and LMVD values from 0/mm2to 22.9/mm2. MVD and LMVD were identified as risk factors for venous and lymphatic invasion of hindgut NETs. Moreover, MVD positively correlated with the maximum diameter of the tumor.


CONCLUSIONS
Tumor progression of NETs may cause angiogenesis and lymphangiogenesis, via an unknown mechanism, as well as lymphovascular invasion. Angiogenesis likely plays an important role in occurrence and progression in the initial phase of hindgut NETs.
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan. yoichiro0207@hotmail.com.
Yoichiro
Y
Okubo
Department of Gastroenterology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Osamu
O
Motohashi
Department of Gastroenterology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Norisuke
N
Nakayama
Department of Gastroenterology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Ken
K
Nishimura
Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Rika
R
Kasajima
Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Yohei
Y
Miyagi
Department of Gastrointestinal Surgery, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Manabu
M
Shiozawa
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Emi
E
Yoshioka
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Masaki
M
Suzuki
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Kota
K
Washimi
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Kae
K
Kawachi
Department of Thoracic Surgery, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Madoka
M
Nito
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Yoichi
Y
Kameda
Department of Pathology, Kanagawa Cancer Center, 2-3-2, Nakao, Asahi-Ku, Yokohama, Kanagawa, 241-8515, Japan.
Tomoyuki
T
Yokose
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000473:pathology*; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007414:Intestinal Neoplasms / Q000473:pathology*; D042583:Lymphangiogenesis; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology*
D014408:Biomarkers, Tumor
Angiogenesis; Hindgut; Microvessel; Neuroendocrine tumor