Identification of copy number alterations associated with the progression of DCIS to Invasive Ductal Carcinoma

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to invasive ductal carcinoma (IDC). Annotation of the genetic differences between the two lesions may assist in the identification of genes that promote the invasive phenotype. Matched IDC and DCIS showed highly similar copy number profiles (average of 83% of the genome shared) indicating a common clonal orgin although there is evidence that the DCIS continues to evolve in parallel with the co-existing IDC. Four chromosomal regions of loss (3q, 6q, 8p and 11q) and four regions of gain (5q, 16p, 19q and 20) were recurrently affected in IDC but not in DCIS. CCND1 and MYC showed increased amplitude of gain in IDC. One region of loss (17p11.2) was specific to DCIS. 21 cases of synchronous DCIS and IDC were microdissected from FFPE tissue and analysed by molecular inversion probe (MIP) copy number arrays. The arrays were early release OncoScan arrays and the data in this submission are CN values for the ~300,000 probes common to two batches performed. Raw data is retained by Affymetrix.