For instance, by expanding the sample size, Zhang J and associates [84] studied 96 cases of ESCC tissues and constructed a PDX model and reported that PIK3CA gene mutation had no apparent impact on the growth of tumors affected by cisplatin or 5-fluorouracil in nude mice, indicating that there was no significant association between the presence of PIK3CA mutation and the likelihood of a response to cisplatin and 5-fluorouracil. This evidence concerns the gene PIK3CA and esophageal squamous cell carcinoma.