The expression of PD-1 ligand 1 on macrophages and its clinical impacts and mechanisms in lung adenocarcinoma.

Programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1) are target molecules for immunotherapy in non-small cell lung cancer. PD-L1 is expressed not only in cancer cells, but also on macrophages, and has been suggested to contribute to macrophage-mediated immune suppression. We examined the clinical significance of PD-L1 expression on macrophages in human lung adenocarcinoma. The mechanism of PD-L1 overexpression on macrophages was investigated by means of cell culture studies and animal studies. The results showed that high PD-L1 expression on macrophages was correlated with the presence of EGFR mutation, a lower cancer grade, and a shorter cancer-specific overall survival. In an in vitro study using lung cancer cell lines and human monocyte-derived macrophages, the conditioned medium from cancer cells was found to up-regulate PD-L1 expression on macrophages via STAT3 activation, and a cytokine array revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was a candidate factor that induced PD-L1 expression. Culture studies using recombinant GM-CSF, neutralizing antibody, and inhibitors indicated that PD-L1 overexpression was induced via STAT3 activation by GM-CSF derived from cancer cells. In a murine Lewis lung carcinoma model, anti-GM-CSF therapy inhibited cancer development via the suppression of macrophage infiltration and the promotion of lymphocyte infiltration into cancer tissue; however, the PD-L1 expression on macrophages remained unchanged. PD-L1 overexpression on macrophages via the GM-CSF/STAT3 pathway was suggested to promote cancer progression in lung adenocarcinoma. Cancer cell-derived GM-CSF might be a promising target for anti-lung cancer therapy.

Accurate expression of PD-L1/L2 in lung adenocarcinoma cells: A retrospective study by double immunohistochemistry.

The percentage of programmed death ligand 1 (PD-L1) positivity in cancer cells, named as the tumor proportion score, is considered to be a predictive biomarker for anti-PD-1/PD-L1 therapy in lung cancer. PD-L1 is expressed on not only cancer cells but also on immune cells, including macrophages. Although previous studies related to PD-L1/2 expression in cancer tissues have been generally based on single immunohistochemistry (IHC), in the present study, we attempted to evaluate accurate PD-L1/2 expression in cancer cells in lung adenocarcinoma cells using double IHC to also evaluate macrophages. Of the 231 patients, PD-L1 expression was negative in 169 patients (73.2%), 1%-49% positive in 47 patients (20.3%), and ≥50% positive in 15 patients (6.5%). Interestingly, PD-L1 positivity was decreased when using double IHC compared with the estimation by single IHC. High PD-L1 expression was associated with high-grade cancer cells and in higher stage cancer. PD-L2 was negative in 109 patients (47.2%), 1%-49% positive in 50 patients (21.6%), and ≥50% positive in 72 patients (31.2%). The number of PD-L2-positive patients was increased in cases that had an epidermal growth factor receptor (EGFR) mutation and in lower stage cancer. Thirty-five patients (15.2%) were positive for both PD-L1 and PD-L2, whereas 81 patients (35.1%) were negative for both PD-L1 and PD-L2. Log-rank analysis showed that progression-free survival and overall survival were significantly the longest in the PD-L1-negative and PD-L2-positive groups (P < .0001 and P = .0120). We observed lower PD-L1 or PD-L2 expression in lung adenocarcinoma than previously reported. Double IHC for macrophages may help clinicians to evaluate PD-L1 or PD-L2 expression specifically in cancer cells.

[A Case of Remnant Gastric Cancer That Completely Responded to Neoadjuvant S-1 and Cisplatin Therapy].

A 69-year-old man, who had undergone distal gastrectomy for duodenal ulcer, was diagnosed with remnant gastric cancer and jejunal mesenteric lymph node metastasis. To improve curability, we planned 2 courses of S-1 and cisplatin therapy. After chemotherapy, primary lesion and lymph node metastases reduced in size drastically. Completion gastrectomy and lymph node dissection were performed with curative intent. The tumor was found to have a pathological complete response(pCR) to chemotherapy on histological examination.

[New FP Therapy Was Effective for a Case of Massive Hepatocellular Carcinoma].

A 62 year-old woman was hospitalized with the diagnosis of pneumonia, and a huge mass was recognized in the right lobe of the liver during a CT scan. AFP and PIVKA-Ⅱ were elevated to 101.05 ng/mL and 2,177 mAU/mL. The liver function test indicated Child-Pugh classification A, liver damage degree B, and ICG R15 34%. We judged a radical cure resection impossible. We treated the patient with arterial injections of modified new FP therapy. No side effect occurred during the first course. Liver dysfunction with fever and hematuria occurred during the second course, leading to discontinuation of therapy. Because a prominent reduction in the size of the tumor was achieved, liver resection is scheduled. New FP therapy can be expected to attain a favorable result that may allow for curative resection of the tumor.

[A Case of Locally Advanced Gastric Cancer after Neoadjuvant Chemotherapy].

A 60s male was admitted to our hospital because of appetite loss and nausea. After examination, he was diagnosed with type 3 advanced gastric cancer in the antrum. Abdominal computed tomography showed gastric cancer invasion to the left liver lobe. We initiated neoadjuvant chemotherapy using S-1 plus CDDP after laparoscopic gastrojejunostomy. S-1 was orally administered for 3 weeks followed by a 2-week drug-free period. CDDP was administered intravenously on day 8 of each course. After 5 courses of chemotherapy, the gastric cancer was reduced in size. We therefore performed total gastrectomy with D2-affiliated left liver resection. S-1 plus CDDP is expected to improve outcomes in unresectable or locally advanced gastric cancer.

[A case of juvenile colon cancer with peritoneal dissemination treated effectively by use of resection and chemotherapy].

A 37 -year-old man experienced abdominal pain and vomiting. Computed tomography showed massive ascites and obstruction of the colon by a tumor at the left colic flexure. The tumor was classified as advanced Borrmann type 3 on the basis of a colonoscopy. Palliative resection of the colon and colostomy on the oral side were performed. Operative findings showed massive peritoneal dissemination of the tumor. We administered palliative chemotherapy consisting of capecitabine/oxaliplatin (XELOX) and bevacizumab. After 4 courses of chemotherapy, the primary and disseminated tumors and ascites had disappeared, and tumor marker expression levels were within normal range. Palliative resection and subsequent chemotherapy was effective for this young patient with very advanced colon cancer that had disseminated and caused obstruction.

[A case of small intestinal gastrointestinal stromal tumor (GIST) with peritoneal dissemination, treated effectively with molecular target drug after operation].

A 54-year-old man, presenting with sudden onset of abdominal pain, was admitted to our hospital. Blood examination revealed high white blood cell counts and elevated C-reactive protein (CRP) levels. Ultrasonography and computed tomography detected a 12 cm mass in the lower abdomen, some ascites, and multiple small nodules spread through the abdomen. The preoperative diagnosis of the tumor was either a gastrointestinal stromal tumor (GIST) or a possible lymphoma. The 12 cm tumor and greater omentum with multiple nodules were resected. Upon pathological examination, the tumor was diagnosed as a GIST, and appeared KIT positive by immunostaining. After the operation, imatinib was administered; however, psoriasis vulgaris developed within 5 months. As the next line of therapy, sunitinib treatment was initiated; however, since peripheral nerve disorder developed, sunitinib dose was halved and maintained. Two years after the operation, the patient is still alive. Small intestinal GISTs, which make up only 20-30% of all GISTs, are considered to be more malignant than others. We report a rare case of GIST with peritoneal metastases originating from the small intestine, which was treated effectively with molecular target drugs.

Gastric Small Cell Neuroendocrine Carcinoma With Loss of Epithelial Markers Expression.

Background/Aim: Given that gastric small cell neuroendocrine carcinoma (SCNEC) is notably more aggressive than conventional adenocarcinoma, and a platinum-based regimen aligned with the treatment for pulmonary SCNEC is advocated when chemotherapy is needed, ensuring an accurate pathological diagnosis is paramount. Case Report: A 63-year-old man, examined for melena, underwent gastroscopy which revealed a total circumferential Borrmann type 3 lesion extending from the pylorus to the antrum of the stomach. He underwent a distal gastrectomy with D2 lymphadenectomy. The microscopic examination revealed SCNEC with a minor adenocarcinoma component. Immunohistochemically, the SCNEC was diffusely positive for synaptophysin, CD56, and INSM1, very focally positive for chromogranin A, and negative for leukocyte common antigen, CD3, and CD20. A significant observation in this case was the complete negativity for epithelial markers including keratin (CK7, CK8, CK20, CAM5.2, and AE1/AE3) and epithelial membrane antigen. Conclusion: Diffuse positivity for neuroendocrine markers, negativity for other lineage markers, and a transition from the adenocarcinoma component, if present, serve as significant diagnostic clues for gastric SCNEC with loss of epithelial markers expression. SCNEC should not be excluded solely based on the negative result for epithelial markers.

GM-CSF derived from the inflammatory microenvironment potentially enhanced PD-L1 expression on tumor-associated macrophages in human breast cancer.

Ever since immune checkpoint inhibitors have been approved for anti-cancer therapy in several cancers, including triple-negative breast cancer, the significance of programmed death-1 ligand 1 (PD-L1) expression in the tumor immune microenvironment has been a topic of interest. In the present study, we investigated the detailed mechanisms of PD-L1 overexpression on tumor-associated macrophages (TAMs) in breast cancer. In in vitro culture studies using human monocyte-derived macrophages, lymphocytes, and breast cancer cell lines, PD-L1 overexpression on macrophages was induced by the conditioned medium (CM) of activated lymphocytes, but not that of cancer cells. Granulocyte-macrophage colony-stimulating factor (GM-CSF) derived from activated lymphocytes was found to be involved in PD-L1 overexpression, in addition to interferon (IFN)-γ, via STAT3 pathway activation. Macrophages suppressed lymphocyte activation, and this inhibition was impaired by PD-1 blocking. The CM of activated lymphocytes also induced the overexpression of PD-L2, but GM-CSF did not affect PD-L2 expression. In the murine E0771 breast cancer model, anti-GM-CSF therapy did not affect PD-L1 expression on TAMs, and the mechanisms of PD-L1 expression on TAMs might differ between humans and mice. However, not only PD-L1, but also PD-L2 was overexpressed on TAMs in the E0771 tumor model, and their expression levels were significantly lower in the tumors in nude mice than in wild-type mice. Anti-PD-L1 antibody and anti-PD-L2 antibody synergistically inhibited E0771 tumor development. In conclusion, PD-L1 and PD-L2 were overexpressed on TAMs, and they potentially contributed to immunosuppression. The GM-CSF-STAT3 pathway is thought to represent a new mechanism of PD-L1 overexpression on TAMs in human breast cancer microenvironment.

Soluble Factors Involved in Cancer Cell-Macrophage Interaction Promote Breast Cancer Growth.

BACKGROUND/AIM: Recent studies have indicated the clinical significance of tumor-associated macrophages (TAMs) in breast cancer; however, the detailed mechanisms of cell-cell interactions between TAMs and cancer cells remain unclear. MATERIALS AND METHODS: In vitro cell culture studies using human monocyte-derived macrophages and breast cancer cell lines were performed to test which cytokines would be involved in cell-cell interactions between cancer cells and macrophages. In addition, studies using human resected samples and animal breast cancer models were performed to examine the significance of TAMs in cancer development. RESULTS: Osteopontin, HB-EGF, and IL-6 were suggested to be macrophage-derived growth factors for breast cancer cells. FROUNT inhibitor significantly blocked TAM infiltration and subcutaneous tumor growth in an E0771 mouse breast cancer model. CONCLUSION: TAMs express growth factors, such as osteopontin, for cancer cells, and targeting of TAM infiltration might be a promising approach for anti-breast cancer therapy.