HA-1 mRNA expression levels in tumor and fibroblast cell lines. Depicted are the relative levels of HA-1 mRNA expression in different cell lines with the use of Raji lymphoma cells as reference. Results were normalized with 18S mRNA. On the basis of a cutoff of 2% compared with the normalized HA-1 mRNA expression level in Raji cells, tumor cell lines were subdivided into HA-1–expressing (ie, HA-1^pos) and HA-1–nonexpressing (ie, HA-1^neg) tumor cell lines.