Exogenous signals from drug-stressed cancer cells promote acquisition of a more aggressive phenotype of neighboring tumor cells. To identify extracellular signaling molecules that potentially contribute to the development of therapy resistance, we examined how cancer cell secretome changes in response to chemotherapy. We performed LC-MS/MS analysis of secretomes from several ovarian cancer cell lines representing different tumor subtypes: serous ovarian cancer cell line (OVCAR3), ovarian cystadenocarcinoma cell line (MESOV) and clear cell ovarian cancer primary culture isolated from ascites (cells 26) before and 48 hours after cisplatin treatment. In addition, we studied secretomes from keratinocyte-derived epithelial cell line HaCaT as non-cancerous “normal” cells. Functional annotation of proteins which secretion increased after cisplatin showed that these proteins were mainly associated with cluster of spliceosome.