On the day of surgery, if the radioactive SLN cannot be located using the gamma probe prior to incision, lymphazurin or methylene blue dye will be used in the breast in the subareolar plexus at the discretion of the surgeon for assistance in identifying the sentinel nodes. This contingency, expected to occur < 3% of the time, will be used since locating the SLN for staging is of greater importance than the study. If radioactive isotope is sufficient to identify the sentinel node draining from the breast, then the blue dye will be injected dermally in the upper inner arm along the bicipital groove of the ipsilateral arm in order to locate the draining lymphatics from the arm. No more than 5cc of blue dye will be injected in any of the above mentioned scenarios. The site of all injections (radioactivity and/or blue dye) will be recorded.