TAT and breast carcinoma: In their 2009 study, Santos-Cuevas et al. proposed a novel hybrid radiopharmaceutical for imaging of prostate and breast cancers, namely 99mTc-Tat-BBN (99mTc-N2S2-Tat(49–57)-Lys3-BBN), which combines targeting properties of BBN with the HIV Tat-derived peptide (Tat(49–57)), a well-characterized cell-penetrating sequence designed to enhance cellular uptake and potentially facilitate nuclear localization.