Please tell me, could a 17 years old boy get breast cancer?

Almost never: It is rare for men to get breast cancer. It is even more rare for a 17-year-old boy to get breast cancer. Boys of this age often get lumps in their breast tissue. It's a normal effect from the hormones being released at puberty. This is common, and it's also common for boys and their parents to worry they have breast cancer. I hope you can relax now!