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. 2015 Jun 1;6(26):22239–22257. doi: 10.18632/oncotarget.4161

Figure 3. Transcriptional co-overexpression of all five OPN isoforms in primary EAC.

Figure 3

A. SPP1 is located in chromosome 4q22.1, spanning 7.76 kb from 87.9756 to 87.9834 Mb in the Contig NC_000004.12. Five isoforms are banked in genome build GRCh38. OPN5 is the only isoform that has exon 4 and an alternative start codon. OPNb lacks exon 6 while OPNc lacks exon 5. OPN4 is the isoform with the shortest transcript, lacking exons 4, 5 and 6. B. Heat map of exome variant analysis using ST 2.1 Affymetrix arrays of 124 primary EACs (exon 6 was not available in the ST 2.1 array). C. Summary of OPN isoform-specific exon expression (0, absence of exon/exons; 1, presence of exon/exons; Frequency, total number of times the exon/exons is expressed across all isoforms). D. Correlation of OPN isoform-specific expression in primary EAC. The mean expression derived from 3 probe sets (2 from exon 7 and 1 from exon 8) with the least deviation among all common exons (1, 2, 3, 7 and 8) was used to represent the total OPN expression. Subtraction of exon 5 expression (specific for isoforms OPNa, b and 5) from the total OPN expression yielded OPNc+4 expression (red dots). Subtraction of exon 4 expression, which was specific for OPN5 (green dots), from exon 5 expression yielded OPNa+b expression (blue dots). These expression levels were then plotted against the total OPN expression for each primary EAC in the arrays. E. Pearson correlation coefficients showed significant correlation between these groups.