I would like to quote ~FlameTwirler in order to inform a little bit about the saint and image for those who are a bit lost about the breasts on the chalice:
"Story of St. Agatha! (Because I was kinda lost too and had to look it up, so I may as well share.) It was one of the tortures she supposedly underwent - her breasts were cut off. Story is that she'd sworn her virginity to God, but a Roman statesman who'd pursued her was rejected by her and didn't take to it too well.
He sent her to a brothel first, then started the torture when that didn't make her fold. First this happened, and she was healed by a vision of Saint Peter. Then he had her rolled naked on a bed of live coals but an earthquake came and toppled a wall onto him, ending the party. She later died in jail. But I think she's actually been adopted recently as the patron saint of breast cancer because of the tie."