Figure 4.

Cluster analysis of array data showing the relative relationship between synchronous breast cancer tumors. Tumor samples with a high degree of similarity are connected to the tree by very short branches. Tumors with decreased similarity are joined by increasingly longer branches. Tumors in patient 8 (P₈T₁ and P₈T₂) and patient 3 (P₃T₁ and P₃T₂) show the greatest degree of similarity to their synchronous counterparts. In patient 6, only tumors P₆T₁ and P₆T₂ are clustered closely, whereas P₆T₃ is only distantly related. Tumors P₁T₃ and P₁T₄ (left breast) from patient 1 also clustered closely but separated from P₁T₁ and P₁T₂ (right breast). Note that not all tumors are matched to their synchronous counterparts. The clustering map was created with Eisen cluster.