Consequently, proteomics analysis-the direct evaluation of the expression levels and modifications of proteins-has been focused on recently as a powerful exploration method for identifying predictive biomarkers for the efficacy of chemotherapeutic medicines. The expression levels of some serum proteins have been reported to be useful FX1 indicators of sensitivity to chemotherapy for cancer, and Li reported that variation in serum LDH level was useful like a predictive biomarker of efficacy of bevacizumab in non-small cell lung cancer (NSCLC) patients (2). L-lactate dehydrogenase B (LDHB) was recognized like a marker of cetuximab level of sensitivity, and it was confirmed that LDHB manifestation was improved in cetuximab-resistant CRC cell lines. Furthermore, LDHB manifestation levels were significantly upregulated with the acquisition of resistance to cetuximab in cetuximab-sensitive CRC cell lines. In conclusion, LDHB was identified as a key point affecting cetuximab level of sensitivity using comprehensive proteome analysis for the first time. reported that only 32% of the genes showed statistically significant positive mRNA-protein correlation in 86 CRC samples (1). Consequently, proteomics analysis-the direct evaluation of the manifestation levels and modifications of proteins-has been focused on recently as a powerful exploration method for identifying predictive biomarkers for the effectiveness of chemotherapeutic medicines. The manifestation FX1 levels of some serum proteins have been reported to be useful signals of level of sensitivity to chemotherapy for malignancy, and Li reported that variance in serum LDH level was useful like a predictive biomarker of effectiveness of bevacizumab in non-small cell lung malignancy (NSCLC) individuals (2). Furthermore, proteomic studies analyzing several serum proteins using matrix-assisted laser desorption/ionization mass spectrometry (VeriStrat; Biodesix, Boulder, CO), classified NSCLC individuals treated with erlotinib, an epidermal growth element receptor (EGFR) tyrosine kinase inhibitor, into two organizations with good or poor prognosis (3C10). However, serum proteins derived from tumor cells and circulating in blood stably represent only a small fraction of total protein derived from a tumor. Therefore, to find more suitable predictive biomarkers for level of sensitivity to anticancer medicines, the analysis should include not only proteins released into blood but all proteins derived from a tumor. In 2015, Sun (11) reported that a higher level of L-lactate dehydrogenase B (LDHB) manifestation in tumor cells was associated with poor overall survival in oral cancer individuals treated with paclitaxel, and Ferrer (12) also reported that 17 kDa membrane-associated protein manifestation in tumor cells could predict level of sensitivity to platinum-based therapy, EGFR inhibitors, and the proteasome inhibitor bortezomib in lung adenocarcinoma in 2018. Inside a meta-analysis of medical studies, Li (13) showed that aldehyde dehydrogenase 1 could be a predictor of response to neoadjuvant chemotherapy in breast cancer. Furthermore, in recent years, proteins in tumor cells have been comprehensively analyzed. Yu (14) recognized some predictive marker proteins for level of sensitivity to platinum-containing medicines in individuals with ovarian malignancy. Moreover, Chauvin (15) recognized predictive marker proteins for the effectiveness of 5-fluorouracil (5-FU) in individuals with locally advanced rectal malignancy. As mentioned above, the usefulness of proteome analysis of tumor cells to develop predictive markers for the effectiveness of certain small molecule drugs has been demonstrated. On the other hand, although L-lactate dehydrogenase A (LDHA) manifestation levels in tumors have been reported to correlate with cetuximab level of sensitivity in individuals with Ewing’s sarcoma (16) and gankyrin has been reported to contribute to resistance to chemotherapy comprising bevacizumab in CRC (17), comprehensive proteome analysis to identify predictive biomarkers for the effectiveness of antibody medicines has not been carried out. Anti-EGFR monoclonal antibodies (anti-EGFR mAbs), including cetuximab and panitumumab, RGS3 are key medicines in the treatment of colorectal malignancy (CRC) and are highly effective for some CRC individuals. On the other hand, anti-EGFR mAbs are very expensive, and are also known to cause severe adverse effects such as an infusion reaction or pores and skin rash. Therefore, these medicines should be used only for individuals in which an effective response is definitely expected. Many medical trials have concluded that variations in the gene are a important factor FX1 influencing the medical effectiveness of anti-EGFR mAbs. Anti-EGFR mAbs have been recommended to be used for wild-type CRC individuals, approximately 60% of all CRC individuals. However, more than 50% of individuals with wild-type tumors do not receive a restorative.