Fas ligand (FasL, Apo-1L/CD95L) expression and clinical outcome in papillary microcarcinoma and papillary thyroid carcinomas with diameter smaller than 1.5 centimeters.
BACKGROUND
The presence and the importance of FasL (FasL, APO-1L/CD95L) in papillary microcarcinoma lesions which are smaller than 1.5 cm of the thyroid is unclear.


OBJECTIVE
It was aimed to investigate FasL expression in papillary microcarcinoma (PMC) of the thyroid.


METHODS
FasL immunoreactivity was evaluated in PMC lesions. Paraffin sections of thyroid specimens obtained from 59 papillary thyroid carcinoma consecutive patients were stained using antibody to FasL. Fas ligand expression and the relation and comparison with clinical and pathological findings in PMC were determined.


RESULTS
There were 39 females (66.1%) and 20 males (33.9%) aged 23-74 years (51.9±11.8 yrs), and 20 patients with tumor size ≤5 mm, 24 patients with 6-10 mm and 15 patients with 10-15 mm. The mean of the intensity and the percentage of FasL immunoreactivity were significantly higher in lesions of PMC than peripheral thyroid tissue (29.5±37.9% and 1.42±1.25 vs. 2.1±5.4% and 0.46±0.95, respectively; p<0.001). Fas ligand immunoreaction were not different according to tumor size, the presence of tumor capsule and tumor invasion, invasion of thyroid capsule, peripheral tissue and vascular structures and multicentricity (p>0.05). However, FasL positivity, staining and intensity were high in patients above 45 years, in oncocytic and tall cell variants, in TNM stage pT4A (p<0.05).


CONCLUSIONS
This study showed that FasL expression (positivity, staining and intensity) was high and increased in PMC of the thyroid tissue, and above 45 years, in tall cell and oncocytic variants, and in advanced tumor.
Bayraktaroglu
T
T
Istanbul University, Istanbul Faculty of Medicine, Division of Endocrinology and Metabolism, Fatih-Istanbul-Turkey. baytaner@yahoo.com
Boztepe
H
H
Kapran
Y
Y
Tanakol
R
R
Alagöl
F
F
D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D053222:Fas Ligand Protein / Q000032:analysis / Q000378:metabolism*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D016896:Treatment Outcome; D055815:Young Adult
D053222:Fas Ligand Protein; D007457:Iodine Radioisotopes