The presence of malignant cells in lymph nodes is a critical parameter in the staging of
melanoma cancer patients. Assessment of lymph nodes is currently done by histopathology
alone. The long-term survival of melanoma cancer patients who have Stage IB disease (no known
lymph node involvement with a tumor greater than 2 cm) is lower than patients who are Stage
IA (no known lymph node involvement with a tumor less than 2 cm). Likewise, the survival
rates of patients who are judged to be Stage II based on histologically positive level-one
lymph nodes is often no better than that of higher stage patients who have level-two lymph
node involvement. These observations suggest that micrometastases are often present in lymph
nodes that are not detectable by histological assessment.
The collection of Sentinel Lymph Nodes (SLN) and non SLN material outlined in this proposal
will permit both targeted and exploratory studies, without compromising the patient's
diagnosis, on specimens that represent central engines of the immune response and whose
function in the context of tumor progression is largely unknown.
With the advent of an array of new methodologies that utilize minimum material for both
molecular and cellular assessments, acquiring up to 20% and in general the investigators
anticipate the use of 5% on average of SLN and/or non SLN tissue for research purposes, may
prove to be critical to understanding the impact of nodal tumor involvement on patient
outcome and survival.