The series' view of selfish self-sacrifice is really interesting. It's not inherently bad, it's just always focused on the person's own desire and it usually turns out bad for the person they're saving not out of malice, but because said person must be victimized if the martyr is determined to sacrifice themselves to save a victim.
Black Jack would also often feature stories where the focus character makes a sacrifice, but I think the primary difference is that they rarely wanted to make the sacrifice, or were fine with it but made the choice in the moment rather than being a premeditated saviour and basking in the idea. They're more pure, while the martyrs in Franken Fran are the people who would have read Black Jack sacrifice chapters and thought "damn, I want to be like that."
Of course these kids also have a beautiful bit of karma to them that's separate from most of the other examples, being spare parts that insist upon being used.