Comment on: Increasing frequency of gene copy number aberrations is associated with immunosuppression and predicts poor prognosis in gastric adenocarcinoma

Dear Editor

We read with great interest the research from Silva et al.¹, which broaden our knowledge on the association between chromosomal status (chromosome-stable (CS), chromosomal instable (CIN)) and prognosis of gastric cancer. However, some points deserve further discussion. The authors should have performed a subgroup analysis of patients with and without chemotherapy. Chemotherapy response and tumour regression grade (TRG) should have been addressed by the authors. Different subtypes of gastric cancer might have distinct responses to chemotherapy and have a significant impact on survival. An earlier study showed that patients with CIN had the most benefit from adjuvant chemotherapy; CS subtype was associated with a poor prognosis. Another study also demonstrated that tumours with a high level of CIN were more likely to benefit from chemotherapy. In addition, chemotherapy may have induced changes in the expression of CIN-associated genes. Second, aberrant p53 expression is associated with the level of CIN. Another study showed that the level of CIN combined with TRG could select a subgroup of patients with a good response to neoadjuvant chemotherapy. Third, the author indicated that stage IV gastric cancers more frequently were CIN. This might be a factor influencing survival data. Clearly, the prognosis of CIN and CS is still controversial and the underlying mechanism needs further investigation.