However, not all breast cancer tissues have detectable OTR expression, either at the mRNA level (positive in 20 out of 27, 74% [68]) or protein level (positive in 7 out of 13, 54% [68], 52 out of 57, 91% [88], and 15 out of 19, 79% [90]). Here, OXTR is linked to breast cancer.