We have also churches which are nurselings of John's: for although Marcion disallows his Apocalypse, yet the succession of their bishops, when traced back to its origin, will be found to rest in John as originator. [Adv Marc 4.5]
For out of those authors whom we possess (Matthew, John, Mark and Luke just mentioned), Marcion is seen to have chosen Luke as the one to mutilate [Adv Marc 4.2]I think a strong circumstantial case can be made that Tertullian assumes Marcion was familiar with the contents of the gospel of John - (a) John knew of the Marcionites thus Marcion's followers (b) they claimed to know the Apocalypse wasn't by John assumes personal knowledge of what John wrote (no mention of a rejection of the gospel) and (c) it is assumed only that the Marcionites corrupted Luke. The context seems to be that Marcion was aware of material from all four gospels and the association with Luke develops only because of Irenaeus's artificial division of four 'heretical types' according to his artificial canon of 'four gospels.' In other words, it is a literary contrivance.