When grossly comparing the MP expression signatures of RGP and VGF hMM presented by Moro and colleagues [7] with herein reported MP transcription data, considerable differences became apparent: Apart from MMP1, other pro-tumoral MPs such as MMP2, MMP13, and MMP14 (MT-MMP1) [5,7,23,24,25,26,27,28,29] showed no deregulation of transcription in gray horse melanoma. Here, MMP13 is linked to melanoma.