In contrast, PIK3CA mutations appear to be similarly frequent in DCIS (24% on average, 17–55%) (63, 64, 69, 70, 74, 83–85) as to IBC (25–36%) (81, 82, 86, 87), although interestingly, several reports have noted the presence of PIK3CA mutation in the DCIS component of mixed DCIS/IBC but absent in the IBC component (64, 83). Here, PIK3CA is linked to ductal breast carcinoma in situ.