Primes in a magic square
A magic square is an arrangement of integers in a square grid, where the numbers in each row, column and main diagonal all add up to the same number, which is called the magic sum.
If we use 9 distinct numbers from 1 to 27 to make a 3 by 3 magic square, what is the most number of primes that we can use?
Details and assumptions
You may use the fact that there are 9 prime numbers from 1 to 27.