Clustering of patients based on the expression data of the 213 FAB subtype-specific genes. Each column represents a patient, and each row represents a gene. Patient numbers are colored according to their FAB subtypes. M2-, M4/M5-, and M7-specific genes are indicated by red (A), green (B), and purple (C) vertical bars, respectively. M2, M4/M5, and M7 clusters of patients are indicated by red, green, and purple horizontal bars, respectively.