Oncological characteristics, treatments and prognostic outcomes in MMR-deficient colorectal cancer.

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally. It's recognized that the molecular subtype of CRC, characterized by mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H), plays a critical role in determining appropriate treatment strategies. This review examines the current molecular classifications, focusing on dMMR/MSI-H CRC and its subtypes: Lynch syndrome (LS), Lynch-like syndrome (LLS), and sporadic cases. Despite advances in understanding of these genetic backgrounds, clinical trials have not conclusively differentiated the efficacy of immune checkpoint inhibitors among these subgroups. Therefore, while this review details the molecular characteristics and their general implications for treatment and prognosis, it also highlights the limitations and the need for more refined clinical studies to ascertain tailored therapeutic strategies for each subtype. Furthermore, this review summarizes completed and ongoing clinical studies, emphasizing the importance of developing treatments aligned more closely with molecular profiles. By discussing these aspects, the review seeks to provide a comprehensive analysis of oncological characteristics, presenting a detailed understanding of their implications for treatment and prognosis in dMMR/MSI-H CRC.

Long-term survival after immunotherapy and targeted therapy without chemotherapy in an elderly patient with HER2-positive gastroesophageal junction cancer: A case report.

A 74-yr-old man underwent thoracic laparoscopy combined with radical gastrectomy, and the postoperative pathological diagnosis was esophageal and gastric cardia cancer pT3N1M0, pStage IIB. Immunohistochemical staining for HER2 (3+) and PD-L1 (<5%) was positive. Adjuvant chemotherapy was not performed because the patient developed severe thrombocytopenia (platelet counts <30 × 109/L), which was never cured throughout the reporting period. At 10.7 months post-surgery, he suffered metastases in multiple organs, including the peritoneum, liver, lung, and bone. Following two cycles of first-line trastuzumab and pembrolizumab (200 mg), he developed immune-related myositis (G2), myocarditis (G2), and hepatitis (G1). Therefore, pembrolizumab was discontinued. Trastuzumab was administered as a monotherapy; meanwhile, adoptive cytokine-induced killer (CIK) cell infusions were initiated. Eight months after the initial immunotherapy, a solitary brain metastasis was detected, and the patient underwent CyberKnife radiosurgery. For second-line therapy, adoptive CIK cell immunotherapy plus trastuzumab was still used. At the time of reporting, the patient had achieved a complete response (CR) in the brain and liver and a partial response (PR) in the ilium, and he had been followed-up for 36.6 months, much longer than the median survival time for patients with advanced GEJ cancer. We suggest that HER2-targeted therapy and immunotherapy with pembrolizumab or CIK adoptive cell infusions prolonged the overall survival of an elderly patient with HER2-positive GEJ cancer with multiple metastases.

A difficult-to-diagnose pericardial fistula.

Pericardial fistula is a rare complication. Generally, the diagnosis can be confirmed by imaging examination, but our patient was an exception. We present a 71-year-old female patient that complained of remnant gastric cancer for five months and dyspnea for seven days; the dyspnea became aggravated during the last two days. After admission, emergency thoracic computed tomography and echocardiography showed pericardial effusion, and pericardiocentesis was performed. After conventional treatment, the pericardial effusion was unchanged and no cancer cells were found in the pericardial drainage. However, the color changed from turbid to golden yellow and, finally, to green. After 20 days of repeated laboratory, imaging, and gastrointestinal contrast examinations, no cause was found. Moreover, a clinical diagnosis could not be obtained following numerous comprehensive clinical analyses. Given the color change of the pericardial drainage, we strongly suspected pericardial fistula, but the imaging examinations were negative. Finally, a methylene blue test confirmed the existence of a pericardial fistula. When the color of the pericardial effusion changes, the existence of a pericardial fistula must be considered in advance, and other methods should be evaluated if imaging cannot assist in the diagnosis.

Role of RECK methylation in gastric cancer and its clinical significance.

AIM: To investigate the relation between RECK methylation and clinicopathological characteristics of gastric cancer patients and evaluate the role of RECK methylation in peritoneal metastasis of gastric cancer. METHODS: Methylation of RECK gene in 40 paired samples of gastric cancer and its corresponding adjacent normal mucosa, lymph nodes and peritoneal irrigation fluid was detected by methylation-specific polymerase chain reaction. RESULTS: Aberrant methylation of RECK gene was detected in 27.5% (11/40) of the adjacent normal mucosa samples, in 47.5% (19/40) of gastric cancer samples, in 57.1% (12/21) of the lymph node samples, and in 35% (14/40) of peritoneal irrigation fluid samples, respectively, with a significant difference between the adjacent normal mucosa and lymph node samples (P = 0.023). Presence of RECK methylation in the primary tumor samples was significantly correlated with tumor invasion (P = 0.023). The accuracy of RECK methylation in peritoneal lavage fluid samples for the diagnosis of peritoneal metastasis of gastric cancer was 72.5% (26/40), with a sensitivity of 66.7% (6/9) and a specificity of 74.2% (23/31). CONCLUSION: Aberrant methylation of RECK gene may provide useful information for the early diagnosis and treatment of peritoneal metastasis of gastric cancer.