NAA50 and neuroblastoma: Furthermore, two neuroblastoma cell lines, COG-N-519 and COG-N-733h, were found to lack a population that stained positive for GD2 surface expression, indicating that not all neuroblastoma cell lines are GD2-positive (Figure 1A,C) while all four neuroblastoma cell lines had detectable levels of HSAN on their surface (Figure 1D).