This approach led us to the discovery of antibodies to 5 interesting melanoma-associated antigens (75 kD glucose-regulated protein (GRP75), 94 kD glucose-regulated protein (GRP94), acid ceramidase (ASAH1), cathepsin D (CTSD), and lactate dehydrogenase B (LDHB)) that correlated with the presence of melanoma within the regional lymph nodes [8]. Here, CTSD is linked to melanoma.