Our previous observations demonstrated that selective and non-selective mACPs responded differently against the same cancer cell lines. In other words, the peptides would present different characteristics for a fixed set of membrane lipid compositions. At first, the 43 selective sequences (ACP-S) contain between 11 and 35 residues (Median: 17, Q1: 15, Q3: 25), whereas their 95 non-selective counterparts (ACP-NS) include between 11 and 84 residues (Median: 17, Q1: 13, Q3: 20.5). Overall, length was not a discriminatory factor. Subsequently, we measured the probabilities of all amino acids for each class, summarised in Table . Small (G, S, P), hydrophobic (I, W, Y, M) and polar (Q, N, T) amino acids populated ACPs at more modest levels. We noted that most mACPs had more positively charged residues (K > H, R) than their negatively charged amino acids (D, E). The high proportions of lysine (K) and leucine (L) are reminiscent of their amphipathic character as membranolytic peptides. None contain cysteine residues. Finally, both alanine (A) and valine (V) were found at higher levels among ACP-S, unlike phenylalanine (F), which was more frequent among ACP-NS. In addition to the amino acid composition analysis, we compared the means of 81 PCPs between ACP-S and ACP-NS. The analysis of different statistical tests, summarised in Figure , showed that 48 PCPs (ACP-S subset) and 19 PCPs (ACP-NS subset) followed normal distributions (ND). Only 14 out of 81 PCPs with an ND coincided with both groups, and the remaining 67 had abnormal distribution (AD). When applying the corresponding variance tests, the Fligner-Killen test indicated that 60 PCPs with AD presented an equal variance and 7 properties had a different variance, whereas the F-test profiled all 14 PCPs with ND to have an equal variance. We identified a total of 31 PCPs with significant differences (p ≤ 0.05). Finally, we adjusted the p-values controlling the false discovery rate leading to a final list of 11 PCPs with significant differences (p ≤ 0.05) between the two mACP classes. In Figure , we detailed the distributions of the 11 PCPs. Five properties informed about different hydrophobicity scales (Chothia hydrophobicity, Zimmerman hydrophobicity, Cruciani Property (CP) hydrophobicity, hydrophobicity index and hydrophobic moment). Most non-selective peptides (ACP-NS) possessed higher levels of hydrophobicity, bulkier and steric properties than their selective counterparts (except for Chothia hydrophobicity scale), which we could associate with their elevated levels of aromatic residues, in particular phenylalanine (cumulative frequency fW,Y,F = 0.098 versus 0.140, ACP-S vs. ACP-NS -Table ). Among the other properties, selective mACPs carried slightly less charged residues (fK,R,H,D,E = 0.317 versus 0.339) than their non-selective counterparts but bore similar enrichments in polar amino acids (fS,T,N,Q = 0.078 vs. 0.081). In contrast, the non-selective mACPs contained fewer small and aliphatic amino acids (fA,G,V,I,L,M = 0.487 vs. 0.413) and presented higher local flexibility indices.