Expression and clinical significance of S100 family genes in patients with melanoma

Abstract

Genes in the S100 family are abnormally expressed in a variety of tumor cells and are associated with clinical pathology, but their prognostic value in melanoma patients has not yet been fully elucidated. In this study, we extracted and profiled S100 family mRNA expression data and corresponding clinical data from the Gene Expression Omnibus database to analyze how expression of these genes correlates with clinical pathology. Compared with normal skin, S100A1, S100A13, and S100B were expressed at significantly higher levels in melanoma samples. S100A2, S100A7, S100A8, S100A9, S100A10, S100A11, and S100P were all highly expressed in primary melanoma samples but were expressed at low levels in metastatic melanoma, and all of these genes were strongly correlated with each other (P<0.001). We found the expression of these S100 family genes to be significantly correlated with both lymphatic and distant melanoma metastasis, as well as with American Joint Committee on Cancer grade but not with Clark's grade, age, or sex. This suggests that expression of these genes may be related to the degree of tumor invasion. Although further validation through basic and clinical trials is needed, our results suggest that the S100 family genes have the potential to play an important role in the diagnosis of melanoma. S100 expression may be related to tumor invasion and may facilitate the early diagnosis of melanoma, allowing for a more accurate prognosis. Targeted S100 therapies are also potentially viable strategies in the context of melanoma.

Fig. 1

Expression levels of S100 family genes in different tissues. (a) S100A1 (b) S100A2, (c) S100A3, (d) S100A4, (e) S100A5, (f) S100A6, (g) S100A7, (h) S100A8, (i) S100A9, (j) S100A10, (k) S100A11, (l) S10012, (m) S10013, (n) S10014, (o) S100B, (p) S100G, and (q) S100P.

Fig. 2

Correlation between S100 family gene expression values and clinicopathological data, P value and log fold change, with FC being equal to the mean expression of the former gene divided by that of the latter gene. (a) A log fold change heatmap was generated, with positive value representing higher expression of the former gene in the two groups being compared, and negative value representing higher expression of the gene in the latter of the two groups compared. (b) A P value heatmap was generated, with grey indicating P<0.01.

Fig. 3

Heatmap of the S100 family genes. (a) A heatmap of all S100 family genes was generated. (b) The first class of S100 family genes is shown on an interrelation heatmap. (c) The second class of S100 family genes is shown on an interrelation heatmap.