Thioredoxin and thioredoxin reductase expression in thyroid cancer depends on tumour aggressiveness.

Thyroid cancer is the second most common malignancy following breast cancer in Arab females. Thioredoxin (TRX) is a small multi-functional redox protein with both intracellular and extracellular functions. The protein exists in either a reduced form (thioredoxin-SH2) or an oxidized form (thioredoxin-S2).

The thioredoxin-thioredoxin reductase system: over-expression in human cancer.

Redox control has emerged as a fundamental biological control mechanism. One of the major redox control systems is the thioredoxin system comprised of thioredoxin (TRX) and thioredoxin reductase (TR). Together they form a powerful system involved in many central intracellular and extracellular processes including cell proliferation, the redox regulation of gene expression and signal transduction, protection against oxidative stress, anti-apoptotic functions, growth factor and co-cytokine effects, and regulation of the redox state of the extracellular environment.

Vascular stroma-derived endothelial colony forming progenitor cells adapt to tumour growth.

Under appropriate nutrient agar culture conditions, primary or xenografted human and animal tumour biopsy-derived cell suspensions will form two types of colony. The first type, consisting of tight colonies of round cells which form tumours when introduced into nude mice, is of neoplastic origin. The second type of colony, the cells of which fail to form tumours on injection into nude mice, consists of loose colonies of larger, inter-connecting elongated bi- or tripolar cells and is thought to originate from vascular stroma-derived endothelial colony forming progenitor cells (V-ECPC).