How lucky she is to have a new friend like you! I agree with the prior posts, just ask how her friends is doing and maybe if she'd like to go out for coffee with you. I'm sure she'd appreciate your concern and maybe talking with you.
Perhaps you can let her know you feel for her by giving her a small packet of notecards? After my dad died a friend of his gave me a box of nice notecards and a few packages of stamps. She knew that people were sending condolence packages, flowers, etc. and her small gift was a very thoughtful way of letting me know she cared.
The notecards would allow her to write her friend, send a picture, etc. to help brighten her friend's day back in Poland. I know that being sick is no fun for anyone. So I'm sure the woman who has cancer would appreciate something picturesque or happy in the mail - especially if she's hospitalized or bedridden.
I hope these suggestions help.