I found some interesting information regarding the connection to tighter bra straps, reduction of movement of lymph and cancer. Have a look at this write up. Please google as much as you can to gather more information but I think it it is something that is worthy of your time. Movement of lymph from the breast tissues is very important.
http://www.healingcancernaturally.com/breast-cancer-bras-lymph-nodes.html
