Fig. 3

a Volcano plot of the gene expression profile data of all 18 patients. x-axis reports difference of the group means while y-axis indicates statistical significance of the t-test per rows (–\(\log _{10}\) of p-value). The dashed line shows where \(p = 0.05\) with points above the line having \(p < 0.05.\) In particular, points represent interesting genes, in the left upper corner are depicted genes with mostly small p-value and low difference in means, whereas in the right upper corner there are genes with small p-value and large difference in means. b Heatmap of the first principal component PC1 and of the Metagene 1 (both normalized) obtained respectively by PCA and NMF on the gene expression profile data of all 18 patients