One hundred twenty-three patients were evaluated and the PIK3CA-H1047R mutation was assayed in sentinel LNs (SLNs), non-SLNs without metastasis, and serum by digital PCR.
This is best illustrated by an activating PIK3CA mutation (H1047R) which was clonal in the primary tumor, but completely absent from either the metastasis or cfDNA.
In addition, the oncogenic PIK3CA(H1047R) mutation was detected in a subpopulation of PV1, but this mutation did not seem to play a major role in vemurafenib resistance in this metastasis.