GDF15 and neoplasm: Gene expression levels of DJ-1, GDF15, and MFGE8 were increased in tumours larger than 6 cm in diameter, with the most prominent and statistically significant increase observed in the GDF15 gene (p = 0.556, p = 0.042, and p = 0.053 for DJ-1, GDF15, and MFGE8, respectively).