The FKNp, FMCm, P248m and FYCp cell lines demonstrated higher expression of HER2 than the FYCp, FMCp and FNNm cell lines; cell line derived from the metastatic tumor (FMCm) shows a higher expression of HER2 compared to the cell line derived from the primary tumor (FMCp). The gene discussed is ERBB2; the disease is neoplasm.