{'fraction_non_alphanumeric': 0.028732683427398667, 'fraction_numerical': 0.007183170856849667, 'mean_word_length': 5.4144736842105265, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Serum follistatin is increased in thyroid cancer and is associated with adverse tumor characteristics in humans.

CONTEXT
Obesity and classical growth factors are associated with thyroid cancer (TC). However, less is known regarding novel hormones such as follistatins and activins. We hypothesized that serum follistatin but not activins would be increased in TC.


OBJECTIVE
To assess circulating levels of follistatins, activins and growth factors in patients with history of TC vs. patients with non-malignant thyroid diseases.


DESIGN AND PATIENTS
Hospital based, unmatched case-control study with 170 thyroidectomized patients due to well-differentiated TC and 106 thyroidectomized patients without history of malignancy. Anthropometric, biochemical and histological parameters were recorded. Serum samples were collected in the steady state 45 days after surgery. Multivariate models were used to adjust for baseline differences of the unmatched variables.


MAIN OUTCOME MEASURES
Serum levels of Follistatin (FST), Follistatin like-3 (FSTL-3), Activin A (ActA), Activin B (ActB), bioactive Insulin-like Growth Factor-1 (bIGF-1) and Stanniocalcin-2 (STC2).


RESULTS
In unmatched univariate models, TC patients had higher FST serum levels compared to cancer-free individuals, independently of histological subtype. In multivariate models adjusting for covariates, subjects in the highest tertile of FST levels were associated with an increased risk for the presence of any type of TC or specific histological subtypes, including papillary; follicular and Hurthle-cell carcinoma; and medullary TC. Higher post-operative FST concentrations were found in patients with vascular invasion and distant metastases and associated with TNM staging at diagnosis.


CONCLUSIONS
FST serum levels are increased in TC patients and correlate with advanced tumor aggressiveness. Future longitudinal studies are needed to confirm and extend our observations.