Background This study evaluated the prognostic value of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) together with host-related factors in patients with unresectable advanced gastric cancer. Methods The study enrolled 262 patients who received chemotherapy for unresectable advanced gastric cancer at Kochi Medical School from 2007 to 2015. Clinicopathological information and systemic inflammatory response data were analyzed for associations between baseline cancer-related prognostic variables and survival outcomes. Results The median survival time was significantly lower for patients with high ALP, high LDH, high total bilirubin, high aspartate aminotransferase, high alanine transaminase, high gamma-glutamyltransferase, high creatinine, a Glasgow prognostic score (GPS) of 1 or 2 score compared to GPS 0, higher compared to lower neutrophil to lymphocyte ratio (NLR) 3.9, lower compared to higher prognostic nutrition index 36.1, T3-4 compared to T1-2 tumor and diffuse-type compared to intestinaltype histology. Multivariate survival analysis identified high ALP 322 (HR 1.808; 95% CI 1.015-3.220; P = 0.044), T2-3 (HR 2.622; 95% CI 1.224-5.618; P = 0.013), and diffuse-type gastric cancer (HR 2.325; 95% CI 1.341-4.032; P = 0.003) as significant independent predictors of worse prognosis in the studied group of cancer patients. Conclusions High level of ALP is an independent, worse prognosis factor for patients receiving chemotherapy for unresectable and recurrent gastric cancer.

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Background Pancreatic cancer (PDAC) is the most lethal malignancy. New treatment options for it are urgently required. The aim was to develop an antibody–drug conjugate (ADC) targeting glypican-1 (GPC-1) as a new therapy for PDAC. Methods We evaluated GPC-1 expression in resected PDAC specimens and PDAC cell lines. We then measured the antitumour effect of anti-GPC-1 monoclonal antibody conjugated with the cytotoxic agent monomethyl auristatin F (MMAF) in vitro and in vivo. Results GPC-1 was overexpressed in most primary PDAC cells and tissues. The PDAC cell lines BxPC-3 and T3M-4 strongly expressed GPC-1 relative to SUIT-2 cells. Compared with control ADC, GPC-1-ADC showed a potent antitumour effect against BxPC-3 and T3M-4, but little activity against SUIT-2 cells. In the xenograft and patient-derived tumour models, GPC-1-ADC significantly and potently inhibited tumour growth in a dose-dependent manner. GPC-1-ADC-mediated G2/M-phase cell cycle arrest was detected in the tumour tissues of GPC-1-ADC-treated mice relative to those of control-ADC-treated mice. Conclusions GPC-1-ADC showed significant tumour growth inhibition against GPC-1-positive pancreatic cell lines and patient-derived, GPC-1-positive pancreatic cancer tissues. Our preclinical data demonstrated that targeting GPC-1 with ADC is a promising therapy for patients with GPC-1-positive pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a stroma-rich cancer. Extracellular matrix proteins produced by cancer-associated fibroblasts (CAFs) found in tumor stroma that impedes effective delivery of chemotherapeutic agents results in poor response in patients with PDAC. Previously, our group reported that glypican-1 (GPC1) was overexpressed in human PDAC and negatively correlated with patient survival. Immunohistochemical analysis of 25 patients with PDAC tumor specimens revealed elevated expression of GPC1 in stromal cells and pancreatic cancer cells in 80% of patients. Interestingly, GPC1 was expressed on CAFs in PDAC. We generated a GPC1 antibody–drug conjugate conjugated with monomethyl auristatin E [GPC1-ADC(MMAE)] and evaluated its preclinical antitumor activity by targeting GPC1-positive CAF and cancer cells in PDAC. GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC cell lines in vitro. Furthermore, GPC1-ADC(MMAE) showed a potent antitumor effect in the PDAC patient-derived tumor xenograft (PDX) model against GPC1-positive CAF and heterogeneous GPC1-expressing cancer cells. Notably, GPC1-ADC(MMAE) showed robust preclinical efficacy against GPC1 in a stroma-positive/cancer-negative PDAC PDX model. GPC1-ADC(MMAE) was delivered and internalized to CAFs. Although apoptosis was not observed in CAFs, the released MMAE from CAFs via MDR-1 induced apoptosis of cancer cells neighboring CAFs and efficiently inhibited PDAC tumor growth. GPC1-ADC(MMAE) exhibited potent and unique antitumor activity in GPC1-positive PDAC PDX models, which suggests that GPC1 is a novel therapeutic target in PDAC and other stromal GPC1-positive solid tumors. These findings show that targeting GPC1 on CAF using GPC1-ADC(MMAE) is a useful approach in case of stroma-rich tumors such as PDAC.

Highlights The authors developed a humanized anti-glypican-1 (GPC1) monoclonal antibody (clone T2) and produced an antibody-drug conjugate (ADC) linked to monomethyl auristatin E (MMAE). The ADC potently inhibited the growth of GPC1-positive pancreatic ductal adenocarcinoma and esophageal squamous cell carcinoma in vitro and in vivo, and exhibited bystander killing activity. Humanized GPC1-ADC(MMAE) was effective against BxPC-3-Luc#2 pancreatic cancer liver metastases in mice. Humanized GPC1-ADC(MMAE) may provide a promising therapeutic strategy for GPC1-positive tumors.