Because of the availability and low cost of BCS, I am going to use this one for MDA-MB-231 breast cancer cell line. But, I see in most of the papers published using FBS for this cell line. Though, I have found a paper (please find the link below) which used 10% BCS for this cell line. However, the pape is pretty old. And for your kind information, I do not see any morphological and growth change after using the 10% BCS. But, to me cells are being acidic quickly after using BCS than FBS.
Article Phospholipase D prevents apoptosis in v-Src-transformed rat ...