GDF15 and neoplasm: Furthermore, GDF15 has shown a correlation with pathological tumor grading, since higher tissue levels, both in vitro (OSCC cell lines) and in vivo (tissue samples from OSCC patients), were associated with higher tumor grading, supporting the hypothesis that GDF15 is involved in promoting dedifferentiation in OSCC via activation of ERK1/2 and p90RSK [140].