A 17-molecule set as a predictor of complete response to neoadjuvant chemotherapy with docetaxel, cisplatin, and 5-fluorouracil in esophageal cancer

Background Recently, neoadjuvant chemotherapy with docetaxel/cisplatin/5-fluorouracil (NAC-DCF) was identified as a novel strong regimen with a high rate of pathological complete response (pCR) in advanced esophageal cancer in Japan. Predicting pCR will contribute to the therapeutic strategy and the prevention of surgical invasion. However, a predictor of pCR after NAC-DCF has not yet been developed. The aim of this study was to identify a novel predictor of pCR in locally advanced esophageal cancer treated with NAC-DCF. Patients and Methods A total of 32 patients who received NAC-DCF followed by esophagectomy between June 2013 and March 2016 were enrolled in this study. We divided the patients into the following 2 groups: pCR group (9 cases) and non-pCR group (23 cases), and compared gene expressions between these groups using DNA microarray data and KeyMolnet. Subsequently, a validation study of candidate molecular expression was performed in 7 additional cases. Results Seventeen molecules, including transcription factor E2F, T-cell-specific transcription factor, Src (known as “proto-oncogene tyrosine-protein kinase of sarcoma”), interferon regulatory factor 1, thymidylate synthase, cyclin B, cyclin-dependent kinase (CDK) 4, CDK, caspase-1, vitamin D receptor, histone deacetylase, MAPK/ERK kinase, bcl-2-associated X protein, runt-related transcription factor 1, PR domain zinc finger protein 1, platelet-derived growth factor receptor, and interleukin 1, were identified as candidate molecules. The molecules were mainly associated with pathways, such as transcriptional regulation by SMAD, RB/E2F, and STAT. The validation study indicated that 12 of the 17 molecules (71%) matched the trends of molecular expression. Conclusions A 17-molecule set that predicts pCR after NAC-DCF for locally advanced esophageal cancer was identified. The aim of this study was to identify the predictors of pCR after NAC-DCF for locally advanced esophageal cancer. We investigated gene expressions in clinical esophageal cancer samples and performed comparisons between pCR cases and non-pCR cases using DNA microarray data and KeyMolnet (KM Data; www.km-data.jp). Esophageal cancer tissue samples were collected at biopsy during endoscopic examination before the administration of the first course of chemotherapy. The biopsy specimen was collected from an elevated part at the proximal side of the tumor in a unified manner. The specimens were frozen and preserved in a freezer maintained at −80℃. The pathological response was evaluated according to the Japanese Classification of Esophageal Cancer 11th edition as follows: grade 0, no recognizable cytological or histological therapeutic effect; grade 1a, viable cancer cells account for two-thirds or more of the tumor tissue; grade 1b, viable cancer cells account for between one-third and two-thirds of the tumor tissue; grade 2, viable cancer cells account for less than one-third of the tumor tissue; grade 3, no viable cancer cells are apparent (pCR). Patients were divided into 2 groups (pCR and non-pCR) according to the pathological response. We analyzed these data using 39 cases. The samples of RNA 1, 4, 7, 10, 12, 17, 24, 29, 35, and 43 were pCR group. The samples of RNA 3, 5, 6, 8, 9, 11, 14, 15, 16, 18, 19, 20, 21, 22, 25, 26, 27, 28, 30, 31, 32, 33, 34, 36, 37, 38, 39, 41, and 42 were non-pCR group.