The Synergistic Antitumor Effect of Combined Anti-Human Epidermal Growth Factor Receptor 2 Antibody and Gamma Interferon Therapy on Antibody-resistant Breast Cancer Cells

The anti-human epidermal growth factor receptor 2 （HER2） antibody （Ab） is a molecularly targeted Ab for cancer therapy. In the field of breast cancer, approximately 20％ overexpress HER2 protein. However, the recurrence rate is 30％ and the metastasis rate is 18％ one year after treatment of anti-HER2 Ab for HER2 positive breast cancer. The resistance to Ab treatment is a major problem for patients. We previously reported that anti-HER2 Ab and Gamma Interferon （IFN-γ） combined therapy show a higher anti-tumor effect than typical therapy in in vitro and in vivo mouse experiments. In this study, we evaluated whether anti-HER2 Ab and IFN-γ combined therapy shows a good synergistic effect against drug-resistant HER2 positive breast cancer cells and a higher antitumor effect than chemotherapy as a conventional clinical treatment. Further, we evaluated a synergy effect with the PD-L1 as a new check point inhibitor. The resistant cell lines were made under the continuous presence of Ab until cell growth was not affected by the drug. The resistant cells were divided into the appropriate number of groups, and then treated with anti-cancer therapy. We evaluated the antitumor effect for both the in vitro study and in vivo mouse xenograft model prepared with the same immunogenicity. The differences of immunofluorescence staining of CD8, Gr-1 and PDL-1 in tissues were investigated, especially in relation to the immune system. The combined therapy showed a significantly higher anti-tumor effect than other groups in in vitro and in vivo experiments. The combined therapy affected anti-tumor immunity in this immunofluorescence experiment. Taken together, we showed the possibility that combined therapy could be an effective treatment option for anti-HER2 Ab resistant breast cancer, thus helping patients suffering from cancer progression after developing treatment resistance

Gastrointestinal Endoscopy for Patients with High Levels of Serum CEA and CA19-9

Serum levels of tumor markers, such as carcinoembryonic antigen （CEA） and carbohydrate antigen 19-9 （CA19-9）, are often measured to detect potential malignancy. When these levels are high, the presence or absence of malignancy is confirmed via a more detailed examination using gastrointestinal （GI） endoscopy and computed tomography. The rate of confirmation of malignancy upon such a follow-up is unknown. This study aimed to investigate the malignancy detection rate via GI endoscopy for patients with high levels of serum CEA and CA19-9. All patients who underwent such GI endoscopy between January 2018 and February 2019 at Showa University Hospital were included in this study. The patients were divided into a follow-up group and a screening group, depending on the purpose of measuring their serum CEA/CA19-9 levels. There were 156 patients who underwent GI endoscopy because of high CEA/CA19-9 levels within the study period. Advanced malignant lesions were detected in 10 patients （6.4％）, including seven cases of colorectal cancer and three cases of upper GI malignancies. In the screening group, six cases （5.7％） of GI malignancies were detected, none of which were found in asymptomatic patients without anemia. In the follow-up group, four cases （7.8％） of GI malignancies were detected; three patients were asymptomatic, and one patient had anemia. Our findings suggest that high serum CEA/CA19-9 levels in asymptomatic patients without anemia and without a history of malignancy do not indicate the presence of malignancy. However, high serum CEA/CA19-9 levels may indicate the potential presence of GI malignancies for patients with a history of malignant tumors, even if they are asymptomatic and do not have anemia

Magnifying Colonoscopy Findings for Differential Diagnosis of Sessile Serrated Adenoma/Polyps and Hyperplastic Polyps

Sessile serrated adenoma/polyps (SSA/Ps) are thought to be precursors of colorectal cancers. However, current endoscopic techniques for differentiating SSA/Ps from conventional hyperplastic polyps (HPs) have low diagnostic accuracy. The aim of the present study was to assess the ability of mucosal crypt patterns to distinguish SSA/Ps from HPs. We examined 140 lesions from 93 patients that had been diagnosed histologically as SSA/Ps or HPs at the Showa University Hospital between June 2010 and May 2012. Three experienced colonoscopists reviewed the endoscopic findings of magnifying colonoscopy. Type II open-shape (Type II-O) pit patterns and varicose microvascular vessels (VMVs) were identified according to previously proposed definitions. Although 140 lesions were initially identified for the study, 27 lesions were excluded from analysis because of insufficient endoscopic findings. Thus, endoscopic findings from a total of 113 lesions (68 SSA/Ps and 45 HPs) were evaluated. Of 113 serrated polyps, 51 lesions (44 SSA/Ps and 7 HPs; P<0.01) had Type II-O pit patterns. The inter- and intra-observer agreement for these patterns among three colonoscopists was κ=0.61 (range 0.57–0.65) and κ=0.68 (range 0.52–0.94), respectively. The positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of Type II-O pit patterns for differentiating between SSA/P and HP were 86%, 61%, 65%, and 84%, respectively. In contrast, the PPV, NPV, sensitivity, and specificity of VMVs were 68%, 43%, 37%, and 73%, respectively. The results indicate that Type II-O mucosal crypt patterns may be useful for the differential diagnosis of SSAPs and HPs

A Synergistic Antitumor Effect of Rituximab and Gamma Interferon Combined Therapy on Human CD20＋ B-Cell Lymphoma Cells

Rituximab （RTX） is an anti-CD20 human-mouse chimeric monoclonal antibody that exhibits antibody-dependent, cell-mediated cytotoxicity and complement-dependent cytotoxicity, resulting in an antitumor effect with immune cells or complement. RTX is approved for the treatment of many diseases including B cell lymphoma and rheumatoid arthritis. We examined whether combined RTX and gamma interferon （IFNγ） therapy provides a higher antitumor effect than RTX single therapy using B-cell lymphoma cells. In addition, we investigated the mechanisms underlying the antitumor effect. We treated tumor-derived cell lines with RTX alone, IFNγ alone, or a combination of RTX and IFNγ（RTX-IFNγ）. Untreated cells served as controls. We experimentally examined in vitro cell proliferation, conducted apoptosis and cell cycle assays, performed Western blotting to identify changes in the levels of proteins related to the cell cycle, and investigated tumor growth in a mouse xenograft experiment. Cell proliferation experiments indicated that RTX or IFNγ alone did not significantly suppress cell growth compared with the control, whereas treatment with RTX-IFNγ significantly suppressed cell proliferation. In vivo mouse experiments also showed that the administration of RTX-IFNγ significantly suppressed tumor growth compared to the single therapies. Some tumors in mice treated with RTX-IFNγ were completely resolved. The cell cycle assays revealed a significantly increased rate of cells in the G0/G1 phase following treatment with RTX-IFNγ compared with the other groups, and the levels of p27kip1 increased and the levels of cyclin E and Cdk 2 decreased in cells treated with RTX-IFNγ. Our findings suggested that RTX-IFNγ combined therapy directly affects cells by arresting the cell cycle at the G1/S checkpoint and had a synergistic antitumor effect compared to RTX single treatment of B-cell lymphomas. This combined therapy may change the mortality rate for B-cell lymphomas

Factors associated with endoscopic treatment decisions for T1b or more deeply invading colorectal cancers

Surgical resection for colorectal cancer（CRC）that deeply invades the submucosa（≥1,000µm）（T1b）has been recommended to reduce the potential risk of lymph node metastasis. In clinical settings, cases of pathological T1b exist, and these cases are treated with endoscopic resection（ER）for various reasons. However, factors that influence the choice of ER to treat T1b CRC remain unknown. Therefore, in this study, we investigated the factors associated with the choice of endoscopic treatments in patients diagnosed with pathological T1b or a more deeply invading CRC. To achieve this aim, we conducted a case series investigation of the previously conducted endoscopic diagnoses, after which we selected treatments for colorectal lesions. The case series comprised 83 lesions endoscopically diagnosed as early CRC, which was subsequently reviewed by eight endoscopists with various levels of experience in magnifying colonoscopy at Showa University Hospital. Then, pathological T1b or T2 lesions were extracted from the case series. We also assessed factors related to ER selection for these lesions using multiple logistic regression and analyzed their contributions using decision tree analysis. Eighteen cases with pathological T1b or more deeply invading lesions were extracted, and the analyses were conducted using 144 data obtained from these 18 lesions as interpreted by the eight reviewers. With multivariate logistic regression, a low estimation level for T1b and high confidence to perform ER were identified as independent factors affecting the selection of ER for T1b. The decision tree analysis further indicated that confidence levels to perform ER influenced treatment selection, especially in lesions diagnosed as probable T1b. Our study therefore demonstrated that factors affecting the selection of ER to treat T1b CRCs were low estimations during endoscopic diagnosis and high confidence to conduct the ER procedure

Accuracy of the Differential Diagnosis of Colorectal Serrated Polyps Using a Conventional Endoscope: A Prospective Study

Some serrated polyps （SPs） are thought to be precursors of colorectal cancers. However, the endoscopic diagnosis of sessile serrated adenoma/polyps （SSA/Ps） has been reported to have a low accuracy. The aim of this study was to clarify the ability to distinguish between SSA/Ps and non-SSA/Ps by using mucosal crypt patterns combined with endoscopic findings. In total, 457 consecutive patients who underwent endoscopic resection for colorectal polyps at the Showa University Hospital from April 2007 to December 2010 were prospectively enrolled in this study. Before treatment, mucosal crypt patterns of the lesions were classified into three types （hyperplastic, adenomatous, and mixed pattern）. When the lesion had an adenomatous pattern with a cerebriform appearance or mixed pattern, it was diagnosed as a traditional serrated adenoma （TSA）. If the lesion had a hyperplastic pattern and was sized 6mm or more in the proximal colon or 10mm or more in the distal colon, it was diagnosed as an SSA/P by the endoscopist. We analyzed 1,151 colorectal polyps in this study. Endoscopically, 117 polyps were diagnosed as SSA/Ps or hyperplastic polyps （HPs）, 998 polyps were conventional adenomas, and 36 polyps were TSAs, with diagnostic accuracies of 94.7％, 94.1％, and 97.3％, respectively. Of the 117 polyps diagnosed as SSA/Ps or HPs, 59 lesions met our criteria for SSA/Ps, with a diagnostic accuracy of 70.9％. Our results indicate that the combination of mucosal crypt patterns and endoscopic findings may be useful for differentiating between SPs and non-SPs. However, additional specific endoscopic features of SSA/Ps are still needed