Clinicopathologic significance of leptin and leptin receptor expressions in papillary thyroid carcinoma.
BACKGROUND
Epidemiologic studies have shown that obesity is associated with an increased risk of thyroid cancer. Leptin, an adipocyte-derived cytokine, can act as a growth factor on certain normal and transformed cells. Aberrant expression of leptin or leptin receptor has been detected in some types of cancer. The aim of this study is to determine immunohistochemical expression of leptin and leptin receptor in papillary thyroid cancer to investigate the relationship between their expression and clinicopathologic features.


METHODS
The expression of leptin and leptin receptor was assessed in 49 primary neoplasms and 15 lymph node metastases using a semiquantitative immunohistochemical staining method.


RESULTS
Leptin and leptin receptor were expressed in 37% and 51% of papillary thyroid cancer, respectively. They were not expressed in normal follicles. In the primary neoplasms and the metastatic nodes, expression of leptin correlated closely with leptin receptor (P < .001 for the primary neoplasms and P = .017 for nodal metastases). Expression of either protein was associated with greater neoplasm size (leptin expression, 32.0 +/- 10.7 vs 20.5 +/- 8.4 mm; P = .001; leptin receptor expression, 27.9 +/- 11.5 vs 21.4 +/- 9.0 mm; P = .032). Coexpression of leptin and leptin receptor in primary neoplasms had greater incidence of lymph node metastasis (P = .038).


CONCLUSIONS
Expression of leptin and/or leptin receptor in papillary thyroid cancer is associated with neoplasm aggressiveness, including tumor size and lymph node metastasis.
Cheng
Shih-Ping
SP
Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan. surg.mmh@gmail.com
Chi
Chin-Wen
CW
Tzen
Chi-Yuan
CY
Yang
Tsen-Long
TL
Lee
Jie-Jen
JJ
Liu
Tsang-Pai
TP
Liu
Chien-Liang
CL
D000328:Adult; D015992:Body Mass Index; D002291:Carcinoma, Papillary / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020738:Leptin / Q000235:genetics* / Q000378:metabolism; D008207:Lymphatic Metastasis / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D054411:Receptors, Leptin / Q000235:genetics* / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*
D020738:Leptin; D054411:Receptors, Leptin