This dataset contains surface meshes and nipple markups acquired in both prone and supine positions from 15 breast cancer cases. Each case includes breast surface meshes, tumor meshes, and nipple markups in both positions. The dataset includes: Prone breast surface meshes (prone_breast_surface.stl) Supine breast surface meshes (supine_surface.stl) Prone and supine tumor meshes (prone_tumor.stl, supine_tumor.stl) Nipple locations in prone and supine positions (prone_nipple.json, supine_nipple.json) Each case is stored in a separate folder (case_01, …, case_15). Usage note:Please cite the related publication when using this dataset:Alfano, F., Navas, P., Lamata, P., Ferreres García, K., Ortuño, J.E., Bueno Zamora, O., Lizarraga, S., Santos, A., Pascau, J., Goicolea, J.M., Ledesma-Carbayo, M.J. "Patient-specific visco-hyperelastic mechanical model for breast tumor localization in surgical planning". Bioeng. Transl. Med., e70044. 2025 (doi: 10.1002/btm2.70044).