PIK3CA and thyroid cancer: Although the above data showed that compared with FTC and ATC, fewer cases of PTC harbored REC8 methylation, we speculated that the large number of PTC tumors in the TCGA database could be sufficient for a replicative study of our findings on REC8. By analyzing thyroid cancer data retrieved from the TCGA database, we indeed demonstrated an association between REC8 hypermethylation and genetic alterations in the PI3K pathway (Figure 6A) and an inverse association between the REC8 mRNA expression and the genetic alterations in the PI3K pathway (Figure 6B).