- Determination of involvement of axillary nodes with metastatic cancer will follow the revised tumor-node-metastasis (TNM) staging system: axillary nodes with single cells with tumor clusters =< 0.2 mm, by either H&E or immunohistochemistry (IHC), will be considered negative axillary node; lymph nodes positive for PCR with tumor cells/clusters < 0.2 mm will be considered negative axillary node; any axillary lymph node with clusters > 0.2 mm will be considered to be positive