Reversal of Immune Suppression in Sentinel Lymph Nodes

Abstract

Minimally invasive intraoperative lymphatic mapping and sentinel node biopsy (LM/SNB) has become the standard approach for staging the regional lymph nodes for early-stage melanoma and breast cancer and has potential applications in other malignancies. The procedure requires close collaboration of surgeon, pathologist, and nuclear medicine physician. The strength of LM/SNB is its accuracy of detecting occult lymph node metastases while the therapeutic value of early dissection of occult metastases is yet unproved. RT-PCR analyses of either fresh frozen or paraffin-embedded sections of the sentinel lymph nodes may be more sensitive than hematoxylin and eosin (H&E) or immunohistochemistry but lack the specificity compared to conventional methods and limits in the availability of tissue specimens make RTPCR impractical for routine use. LM/SNB allows for focused analysis of the matched primary malignancy and sentinel node. Research from human melanoma specimens suggest the sentinel node (SN) has molecular properties pointing toward immune dysfunction of these lymph nodes as compared with adjacent non-SNs and that reversal of this dysfunction may be an effective method of enhancing the immune response to melanoma.