EGF and cancer: For example, one study using normal breast organoid cultures created a defined chemoattractant gradient, using growth factors such as epidermal growth factor, to direct the formation of epithelial branches.65 This approach allows tissue-specific spatial and chemical factors to be considered in organoid cultures and, furthermore, can be adapted for use in cancer research—for example, to provide insights into factors that contribute to the loss of breast tissue organisation during carcinogenesis.