The method comprises: (a) isolating a sample from the breast tumour; (b) determining the level of expression of GRP94, FN14 or both in the sample, and (c) comparing said level with the level of said gene(s) in a control sample, wherein if it is detected an overexpression of said gene(s), in respect of the control sample, it is indicative of the risk for developing brain metastasis. The kit to carry out the method of the invention comprises appropriate means to determine the level of expression of each one of the markers. Both, the method and kit provides accurate information about the risk of developing brain metastasis in an early state, which can lead to a reduction of the incidence of breast cancer brain metastasis.