Expression of inducible nitric oxide synthase in thyroid neoplasms: immunohistochemical and molecular analysis.
To understand the role of inducible nitric oxide synthase (iNOS) in thyroid tumorigenesis, immunohistochemical staining of 36 surgical specimens of thyroid neoplasm that consisted of seven follicular adenomas, 12 papillary carcinomas, seven follicular carcinomas, five medullary carcinomas, and five anaplastic carcinomas were analyzed. In addition, 20 specimens of normal thyroid were used as control samples. Reverse transcription-polymerase chain reaction and western blot analysis were also performed using a normal thyroid and a representative papillary carcinoma case. The intensity and proportion of the immunostained tumor cells were graded semiquantitatively. The grades of the intensity and the proportion were then summed to provide an immunohistochemical score. There was a variation in the staining intensity and proportion. The iNOS expression was low in normal follicular epithelia. Inducible nitric oxide synthase is present in the majority of thyroid tumor cells, including follicular adenomas, papillary carcinomas, follicular carcinomas, medullary carcinomas, and anaplastic carcinomas. Relatively low expression was shown in follicular neoplasms. Only a few inflammatory cells in the stroma were immunoreactive. These results suggest that iNOS may have a role in tumorigenesis, and iNOS in human thyroid carcinoma is mostly derived from tumor cells not from macrophages.
Choe
Wonsick
W
Department of Nuclear Medicine, Inha University College of Medicine, Incheon, Korea.
Kim
Sungeun
S
Hwang
Tae Sook
TS
Lee
Seung Sook
SS
D018263:Adenocarcinoma, Follicular / Q000201:enzymology / Q000473:pathology; D000236:Adenoma / Q000201:enzymology* / Q000473:pathology; D015153:Blotting, Western; D002277:Carcinoma / Q000196:embryology* / Q000201:enzymology / Q000473:pathology; D018276:Carcinoma, Medullary / Q000201:enzymology / Q000473:pathology; D002291:Carcinoma, Papillary / Q000201:enzymology / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000201:enzymology; D013964:Thyroid Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000601:surgery
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II