Molecular characterization of inflammatory genes in sentinel and nonsentinel nodes in melanoma.
OBJECTIVE
Identification of regional node metastasis is important for accurate staging and optimal treatment of early melanoma. We hypothesize that the nodal profile of immunoregulatory cytokines can confirm the identity of the first tumor-draining regional node, i.e., the sentinel node (SN) and indicate its tumor status.


METHODS
RNA was extracted from freshly dissected and preserved nodal tissue of 13 tumor-negative SNs, 10 tumor-positive SNs (micrometastases <2 mm), and 11 tumor-negative non-SNs (NSN). RNA was converted into cDNA and then amplified by PCR. Expression of 96 cytokines and chemokines was assessed using cDNA microarray and compared by using hierarchical clustering.


RESULTS
Fifty-seven genes were expressed at significantly (P < 0.05) different levels in SNs and NSNs (4 genes had higher expression, and 53 genes had lower expression in SNs). Expression levels of interleukin-13 (IL-13), leptin, lymphotoxin beta receptor (LTbR), and macrophage inflammatory protein 1b (MIP1b) were significantly higher (P < 0.04, P < 0.01, P < 0.05, and P < 0.01, respectively), and expression level of IL-11Ra was lower (P < 0.03) for tumor-positive as compared with tumor-negative SN. Receiver-operator characteristics curve analyses showed that the area under the curve (AUC) for IL-13, leptin, LTbR, MIP1b, and IL-11Ra was 0.79, 0.83, 0.75, 0.81, and 0.77, respectively. The AUC for the five genes in combination was 0.973, suggesting high concordance of gene-expression profiles with SN staging.


CONCLUSIONS
SNs have a different immunoregulatory cytokine profile than NSNs. The cytokine profile of tumor-positive SNs; increased expression of IL-13, leptin, LTbR, and MIP1b and decreased expression of IL-11Ra, may provide clues to the local tumor lymph node interaction seen in the earliest steps of melanoma metastasis.
Torisu-Itakura
Hitoe
H
Department of Molecular Therapeutics , John Wayne Cancer Institute at Saint John's Health Center, Santa Monica, California 90404, USA.
Lee
Jonathan H
JH
Scheri
Randall P
RP
Huynh
Young
Y
Ye
Xing
X
Essner
Richard
R
Morton
Donald L
DL
D017252:CD3 Complex / Q000096:biosynthesis; D045744:Cell Line, Tumor; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007249:Inflammation; D018793:Interleukin-13 / Q000096:biosynthesis; D020738:Leptin / Q000378:metabolism; D008198:Lymph Nodes / Q000473:pathology; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D009362:Neoplasm Metastasis; D053702:Receptors, Interleukin-11 / Q000096:biosynthesis; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology*
D017252:CD3 Complex; D018925:Chemokines; D016207:Cytokines; D018793:Interleukin-13; D020738:Leptin; D053702:Receptors, Interleukin-11