As a specific antibody that exclusively detects t-DARPP was not available, we initially used the C-terminal DARPP-32 antibody (H-62; Santa Cruz Biotechnology), which detects both t-DARPP and DARPP-32 proteins, for immunohistochemical staining on tissue microarrays containing 59 primary breast tumor samples (FULL MOON Biosystems & AccuMax Array). This evidence concerns the gene PPP1R1B and breast neoplasm.