Well if you look at the data sheet and the schematic you will see that 4 of the analogue inputs are used for other things:-
PA11 - TXdata2
PB12 SDA0 - 3
PB13 SCL0 - 3
PB21 Rx3
That means they are switched to those alternate functions and they are wired up on the board as if they were those functions. So yes if you want to hack the tracks and initialise those as analogue functions you can do, but you then loose the functionality of what they are assigned to at the moment.