Detection of Circulating and Disseminated Tumor Cells and Their Prognostic Value under the Influence of Neoadjuvant Therapy in Esophageal Cancer Patients

Microscopic venous invasion is a predictor of prognosis in patients with esophageal squamous cell carcinoma undergoing ineffective neoadjuvant chemotherapy and surgery

BACKGROUND

Neoadjuvant chemotherapy followed by surgery is Japan's most effective treatment modality for advanced thoracic esophageal squamous cell carcinoma. However, the prognosis is not as expected. This study aimed to examine prognostic factors in patients with pathologically ineffective neoadjuvant chemotherapy followed by surgery for esophageal squamous cell carcinoma.

METHODS

We retrospectively analyzed patients who underwent neoadjuvant chemotherapy followed by curative esophagectomy for esophageal squamous cell carcinoma between December 2008 and July 2021. The patients were divided into the neoadjuvant chemotherapy effective group and the neoadjuvant chemotherapy ineffective group according to the pathological diagnosis. Clinicopathological data, prognosis, and recurrence were analyzed.

RESULTS

A total of 143 patients (121 males, 22 females; median age, 67 years) were included in this study. Of these, 34 patients were classified into the effective group and the remaining 109 patients were assigned to the ineffective group. The ineffective group had significantly worse overall survival and recurrence-free survival than the effective group (p = 0.0192 and p = 0.0070, respectively). In the ineffective group, multivariate analysis demonstrated that microscopic venous invasion was an independent prognostic factor for overall survival (hazard ratio 2.44; 95% confidence interval 1.13-5.30) and recurrence-free survival (hazard ratio 2.43; 95% confidence interval 1.24-4.73).

CONCLUSIONS

Microscopic venous invasion was associated with poor survival and cancer recurrence in the neoadjuvant chemotherapy ineffective group of patients who underwent esophagectomy for esophageal squamous cell carcinoma.

Combining Solid and Liquid Biopsy for Therapy Monitoring in Esophageal Cancer

Esophageal cancer (EC) has one of the highest mortality rates among cancers, making it imperative that therapies are optimized and dynamically adapted to individuals. In this regard, liquid biopsy is an increasingly important method for residual disease monitoring. However, conflicting detection rates (14% versus 60%) and varying cell-free circulating tumor DNA (ctDNA) levels (0.07% versus 0.5%) have been observed in previous studies. Here, we aim to resolve this discrepancy. For 19 EC patients, a complete set of cell-free DNA (cfDNA), formalin-fixed paraffin-embedded tumor tissue (TT) DNA and leukocyte DNA was sequenced (139 libraries). cfDNA was examined in biological duplicates and/or longitudinally, and TT DNA was examined in technical duplicates. In baseline cfDNA, mutations were detected in 12 out of 19 patients (63%); the median ctDNA level was 0.4%. Longitudinal ctDNA changes were consistent with clinical presentation. Considerable mutational diversity was observed in TT, with fewer mutations in cfDNA. The most recurrently mutated genes in TT were TP53, SMAD4, TSHZ3, and SETBP1, with SETBP1 being reported for the first time. ctDNA in blood can be used for therapy monitoring of EC patients. However, a combination of solid and liquid samples should be used to help guide individualized EC therapy.

Emerging roles of cystathionine β-synthase in various forms of cancer

The expression of the reverse transsulfuration enzyme cystathionine-β-synthase (CBS) is markedly increased in many forms of cancer, including colorectal, ovarian, lung, breast and kidney, while in other cancers (liver cancer and glioma) it becomes downregulated. According to the clinical database data in high-CBS-expressor cancers (e.g. colon or ovarian cancer), high CBS expression typically predicts lower survival, while in the low-CBS-expressor cancers (e.g. liver cancer), low CBS expression is associated with lower survival. In the high-CBS expressing tumor cells, CBS, and its product hydrogen sulfide (H₂S) serves as a bioenergetic, proliferative, cytoprotective and stemness factor; it also supports angiogenesis and epithelial-to-mesenchymal transition in the cancer microenvironment. The current article reviews the various tumor-cell-supporting roles of the CBS/H₂S axis in high-CBS expressor cancers and overviews the anticancer effects of CBS silencing and pharmacological CBS inhibition in various cancer models in vitro and in vivo; it also outlines potential approaches for biomarker identification, to support future targeted cancer therapies based on pharmacological CBS inhibition.