Deletion hotspots of <i>AMACR</i> CGI and their relation to the level of AMACR expression and colon histological entity.

Samples were divided into five groups according to their AMACR expression score (Left) or into six groups according to their histologic entity (Right). Left: Deletion at CG3 (Δ3 only) fluctuated as AMACR expression level went from 0 to 4; deletion at CG10 (Δ10 only) was a rare (≤5%) event in colon cells; Notably, CG3 and 10 double-deletions (Δ3 & 10, bold) were the only deletions identified in groups with low AMACR expression (score: 0–1). Frequent CG12-16 deletion (Δ12-16 only, bold) was correlated with high AMACR expression (53%, 67% and 66%, respectively. Score: 2–4). The rest of deletion combinations (Δ3 & 12-16; Δ10 & 12-16; and Δ3, 10 & 12-16) were not found or were at a low level (<2.5%). Right: Double-deletions at CG3 and 10 were found only in the normal and TA samples and notably absent in VA and CCas of all grades. CG12-16 deletion was found in all the sample groups but occurred at higher frequencies in well- and moderately differentiated cancers (56% and 89%, respectively). In contrast, in the poorly differentiated cancers, the sequence of the CGI was largely unchanged (72%) with only 14% deletion of CG12-16. Mutual exclusion of deletion at CG12-16 and double-deletion at CG3 and 10 (0%) is one of the features of the samples studied. Compared with the moderately differentiated group that has the highest deletion rate, significant difference of CG12-16 deletion was identified in the asterisk marked groups (*, p<0.05).