Which brings up another point not proving Rome necessarily, but definitely consistent with it. Mark was by universal tradition the interpreter of St. Peter who wrote His Gospel based on Peter's teaching in Rome.
Which is why it is intriguing that Mark's Gospel--unlike the other three--is chock full of Hellenized Latin terms:
4:27 modios/modius (a measure)
5:9,15: legiôn/legio (legion)
6:37: dênariôn/denarius (a Roman coin)
15:39, 44-45: kenturiôn/centurio (centurion; both Matthew and Luke use ekatontarchês, the equivalent term in Greek).
It's not as solid as the other evidence, but it is definitely very much consistent with a Roman setting, and it tends to disfavor a setting in the East.
Dear friend ,thank you for pointing this out. I never picked up on that before.
I wish you a Blessed Day!