ERBB2 and breast cancer: The synthetic approach presented here allows the model to be easily customised to other populations as better estimates become available.44 45 Although we used the associations between PVs and tumour ER and TN status, the models do not currently consider the associations with intrinsic BC subtypes based on combinations of ER, progesterone receptor, HER2 and/or grade.19 The methodology described here could be used to further extend the models to consider these BC subtypes.