Fig. 4

Comparison of HLA expression patterns in primary tumor and metastatic tumor samples. The distribution of (a) HLA-A and (b) HLA-B/C expression in LN is significantly different between patients with SCC and AC (for both P = 0.045, Chi² test). In SCC, more complete loss of HLA-A expression was observed in primary tumor and LN, while in AC, there was more weak expression of HLA-A in primary (P = 0.053, pairwise Chi² test) tumor and LN (P = 0.081, pairwise Chi² test). NB: We cannot exclude the possibility of HLA haplotype loss or HLA allelic loss as previously described [19] in the cases defined as having ‘normal HLA expression’ since these were solely based on HCA2 and HC10 staining