title: Prognostic value of p27 in follicular thyroid carcinoma and its relation to radioactive iodine response: does it aid in the modification of risk stratification?
abstract: BACKGROUND
  Follicular thyroid carcinoma (FTC) is the second most common type of thyroid cancer. Genetic studies have demonstrated that the loss of expression and function of Cdk inhibitor p27 leads to the development of multiple-organ hyperplasia and malignancy, including thyroid carcinoma.
  
  
  OBJECTIVE
  (1) To assess the prognostic value of the quantitative expression of p27 in correlation with clinicopathologic prognostic indicators in FTC. (2) To explore its predictive value in the assessment of response to radioactive I-131 therapy in metastatic FTC patients.
  
  
  METHODS
  This retrospective study was conducted on 43 histopathologically confirmed FTC patients referred to the nuclear medicine department, National Cancer Institute, Cairo University between July 2001 and December 2010, for radioactive I-131 therapy. Clinicopathologic parameters, details of radioactive I-131 therapy and its outcome, and a serial follow-up serum thyroglobulin levels and I-131 whole body scan were obtained from their medical records. Quantitative expression of p27 using immunostaining was analyzed using paraffin blocks of thyroidectomy specimens in all patients.
  
  
  RESULTS
  With respect to clinicopathologic characteristics, p27 expression was found to be significantly lower in patients with vascular invasion (P=0.024) and in patients with an advanced-stage disease (P=0.048). A significant difference was detected between the risk stratification and the quantitative expression of p27. A statistically significant difference was obtained with respect to immunohistochemical expression of p27 between the metastatic and nonmetastatic patients as well as age, growth characteristics, tumor size, vascular invasion, and extrathyroidal extension. Despite the observed trend in patients with a low p27 expression, to have a worse response to iodine therapy, and a poor overall survival, the point of statistical significance could not be reached.
  
  
  CONCLUSIONS
  In this preliminary study, p27 quantitative expression appeared to provide a complementary valuable predictor with other prognostic variables for risk stratification in FTC patients. Response to I-131 therapy in FTC in relation to p27 expression should be thoroughly investigated including large-scale studies and more homogenous risk groups.
authors.affiliation: *Nuclear Medicine Department †Pathology Department, National Cancer Institute, Cairo University ‡Radiology Department §Nuclear Medicine Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Magdy Hassan
authors.initials: MH
authors.lastname: Kotb
authors.forename: Ahmed Mohamed
authors.initials: AM
authors.lastname: Zaher
authors.forename: Mai Amr
authors.initials: MA
authors.lastname: Abd El-Wahab
authors.forename: Iman Loay Hussein
authors.initials: IL
authors.lastname: Abulkheir
authors.forename: Manar
authors.initials: M
authors.lastname: Hussein
authors.forename: Shahenda Sabry
authors.initials: SS
authors.lastname: Salem
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D000293:Adolescent; D000328:Adult; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy
chemical_list: C436291:CDKN1B protein, human; D007457:Iodine Radioisotopes; D050760:Cyclin-Dependent Kinase Inhibitor p27