RESUMO
Gastric and gastroesophageal junction (GEJ) cancers represent an aggressive group of malignancies with poor prognosis even when diagnosed in relatively early stage, with an increasing incidence both in Asia and in Western countries. These cancers are characterized by heterogeneity as a result of different pathogenetic mechanisms as shown in recent molecular analyses. Accordingly, the understanding of phenotypic and genotypic correlations/classifications has been improved. Current therapeutic strategies have also advanced and moved beyond surgical extirpation alone, with the incorporation of other treatment modalities, such as radiation and chemotherapy (including biologics). Chemoradiotherapy has been used as postoperative treatment after suboptimal gastrectomy to ensure local disease control but also improvement in survival. Preoperative chemoradiotherapy/chemotherapy has been employed to increase the chance of a successful R0 resection and pathologic complete response rate, which is associated with improved long-term outcomes. Several studies have defined various chemotherapy regimens to accompany radiation (before and after surgery). Recently, addition of immunotherapy after trimodality of gastroesophageal cancer has produced an advantage in disease-free interval. Targeted agents used in the metastatic setting are being investigated in the early setting with mixed results. The aim of this review is to summarize the existing data on trimodality approaches for gastric and GEJ cancers, highlight the remaining questions and present the current research effort addressing them.
RESUMO
Intratumoral heterogeneity (ITH) is a fundamental property of cancer; however, the origins of ITH remain poorly understood. We performed single-cell transcriptome profiling of peritoneal carcinomatosis (PC) from 15 patients with gastric adenocarcinoma (GAC), constructed a map of 45,048 PC cells, profiled the transcriptome states of tumor cell populations, incisively explored ITH of malignant PC cells and identified significant correlates with patient survival. The links between tumor cell lineage/state compositions and ITH were illustrated at transcriptomic, genotypic, molecular and phenotypic levels. We uncovered the diversity in tumor cell lineage/state compositions in PC specimens and defined it as a key contributor to ITH. Single-cell analysis of ITH classified PC specimens into two subtypes that were prognostically independent of clinical variables, and a 12-gene prognostic signature was derived and validated in multiple large-scale GAC cohorts. The prognostic signature appears fundamental to GAC carcinogenesis and progression and could be practical for patient stratification.