PD-1 and PD-L1 blockade in gastrointestinal malignancies

Characterisation of PD-L1-positive subsets of microsatellite-unstable colorectal cancers

Background:

The aim of this study was to reveal the clinicopathological and molecular characteristics of microsatellite instability-high (MSI-H) colorectal cancers (CRCs) showing programmed death ligand-1 (PD-L1) positivity, which are good candidates for anti-PD-1/PD-L1 immunotherapy.

Methods:

The PD-L1 expression status of 208 MSI-H CRCs was retrospectively analysed using immunohistochemistry. PD-L1 positivity in tumour cells (PD-L1+(T)) and PD-L1 positivity in immune cells (PD-L1+(I)) were separately evaluated.

Results:

Programmed death ligand-1 positivity in tumour cells and PD-L1+(I) were observed in 26 (12.5%) and 62 (29.8%) MSI-H CRCs, respectively, and occasionally overlapped (n=12; 5.8%). Programmed death ligand-1 positivity tumours in MSI-H CRCs were significantly associated with older age, female sex, non-mucinous-type poor differentiation, infiltrating growth, tumour budding, advanced stage, CpG island methylator phenotype-high, MLH1 promoter methylation, and BRAF V600E mutations. However, PD-L1+(I) MSI-H CRCs were characterised by high-density tumour-infiltrating immune cells, including T cells and macrophages, and intense peritumoural lymphoid reactions. In patients with stage IV MSI-H CRCs who had undergone metastatectomy (n=4), the PD-L1 status of primary tumours was maintained in corresponding distant metastatic lesions.

Conclusions:

In MSI-H CRCs, PD-L1+(T) and PD-L1+(I) are linked to a sporadic hypermethylated subtype and an immune cell-rich subtype, respectively. Potential differential therapeutic implications of PD-L1+(T) and PD-L1+(I) in CRCs should be further investigated.

Current Advancement in Multidisciplinary Treatment for Resectable cStage II/III Esophageal Squamous Cell Carcinoma in Japan

Multidisciplinary treatment comprising surgery, chemotherapy, and radiotherapy for resectable esophageal squamous cell carcinoma (ESCC) is widely used with improved prognosis. Transthoracic esophagectomy (TTE) with extended lymph node (LN) dissection, known as three field LN dissection, has been recommended for ESCC using open thoracotomy or the thoracoscopic approach. The Japan Clinical Oncology Group (JCOG) trial (JCOG1409) is investigating the patients' long term survival using the thoracoscopic approach that has been shown to reduce the incidence of postoperative respiratory complication. For perioperative treatment, neoadjuvant chemotherapy using cisplatin plus 5-fluorouracil (5-FU), has been accepted as the standard of care in Japan based on the JCOG9907 trial. In Western countries, neoadjuvant chemoradiotherapy was shown to prolong overall survival for esophageal cancer, including ESCC. Although surgery has been recognized as an initial curative treatment for esophageal cancer, definitive chemoradiotherapy is an alternative treatment for patients who are unable to undergo thoracotomy or who decline to undergo surgery. This article reviews multidisciplinary treatment advances for ESCC. However, current standard treatments are country dependent and the ongoing trial may help standardize ESCC treatment across various societies.

Serum levels of soluble programmed cell death ligand 1 as a prognostic factor on the first-line treatment of metastatic or recurrent gastric cancer

PURPOSE

Immune checkpoint molecules are key targets for the treatment of various malignancies. Due to the heterogeneity of advanced gastric cancer (GC), the role of programmed cell death ligand 1 (PD-L1) expression as a tumor biomarker remains controversial. In this study, the prognostic value of soluble PD-L1 (sPD-L1) levels in serum samples was assessed in patients with metastatic GC.

METHODS

All patients received first-line treatment with fluoropyrimidine and platinum chemotherapy, and trastuzumab was added for HER2-positive patients. Serum levels of sPD-L1 were measured by enzyme-linked immunosorbent assay.

RESULTS

Among 75 metastatic GC patients, the median serum sPD-L1 level was 0.704 ng/ml (range <0.156-3.214). Serum sPD-L1 was significantly higher in patients with a high versus a low white blood cell count at baseline. When the cutoff value was set as the median, multivariate analyses showed that high sPD-L1 levels were associated with worse overall survival compared with low sPD-L1 levels (HR 2.218, 95 % CI 1.139-4.320, P = 0.019). Regardless of HER2 status, overall survival tended to be shorter in patients with high sPD-L1 compared with low sPD-L1. There was no significant association between sPD-L1 level and progression-free survival on the first-line treatment of metastatic GC.

CONCLUSIONS

High serum levels of sPD-L1 correlated with worse overall survival on the first-line chemotherapy in metastatic GC patients.