Neuroblastoma Breakpoint Figure 4. Expression analysis of the NBPF gene family in neuroblastoma cell lines and tumors. (A) Real-time quantitative RT-PCR analysis of the NBPF gene family in a panel of neuroblastoma cell lines. Four different amplicons on the NBPF cDNA were chosen, of which A and C can have several copies in a single NBPF transcript [27]. The top panel shows the location of these amplicons in the standard NBPF1 transcript. Amplicon A is present in two copies in this particular transcript. Expression levels were normalized to four reference genes [19], and the lowest value was set to 1. (B) Neuroblastoma cell lines were grouped according to the NBPF1 status (heterozygous NBPF1 deletion or not). For all amplicons, this resulted in a PLoS ONE | www.plosone.org 7 May 2008 | Volume 3 | Issue 5 | e2207