There was a significant progressive increase in the percent of PTHrP expression from normal breast (mean ± SD of 64.86 ± 11.58, median of 65.0) to adjacent DCIS lesions (mean ± SD of 68.06 ± 7.92, median of 65.0) peaking in IBC-NST cases (mean ± SD of 80.53 ± 8.91, median of 80.0) (p < 0.001). Here, PTHLH is linked to ductal breast carcinoma in situ.