can a woman with breast cancer breastfeed a baby? not taking anything treatment….what are the symptoms?

I am 37y ears old,and i have an 9 month old baby,i am currently breastfeeding him,but i am suspicious about having breast cancer,i am not certain but i think i may have,my question was if this can affect the baby,that if i may have breast cancer i am still breast feeding him,can this affect the child? ( i am not taking any treatment,no drugs or anything of any treatment) i am going to check myself with a doctor,but i am curious to know if i should continue breast feeding if i had breats cancer.
EDIT:My mom posted this question,and detail she said that she has breast pain,swollen,like a crown forming around her nipple and new veins appearing.