Hepatitis B virus infection and B-cell non-Hodgkin's lymphoma in a hepatitis B endemic area: a case-control study

Several studies have reported a higher prevalence of chronic hepatitis C virus (HCV) infection in patients with B-cell non-Hodgkin's lymphoma and suggested a pathogenic role for HCV, but studies on hepatitis B virus (HBV) infection and non-Hodgkin's lymphoma are limited. To determine the association between HBV infection and non-Hodgkin's lymphoma, we performed a case-control study in Korea, a hepatitis B endemic area. We recruited 222 patients newly diagnosed with non-Hodgkin's lymphoma at Seoul National University Hospital between January 1997 and December 1998 as cases. Four age- and sex-matched controls were selected for each case, and the control groups comprised of 439 patients with non-hematological malignancy (control group 1) and 444 subjects with non-malignant conditions (control group 2). Relative risk of developing non-Hodgkin's lymphoma among individuals tested positive for hepatitis B surface antigen was calculated after controlling for other potential risk factors of lymphoma, such as smoking, alcohol drinking, transfusion history and HCV infection. Hepatitis B surface antigen was positive in 28 of 222 patients (12.6%) with non-Hodgkin's lymphoma compared with 32 of 439 (7.3%) in control group 1, and 21 of 444 (4.7%) in control group 2 (P = 0.001). The crude odds ratio for B-cell non-Hodgkin's lymphoma among the HBV carriers was 2.54 (1.46 - 4.45) and the adjusted odds ratio was 3.30 (1.69 - 6.45) by multivariate analysis. The present study suggests that the risk of B-cell non-Hodgkin's lymphoma is increased in HBV carriers and warrants further investigation of the possible role of hepatitis B virus in the pathogenesis of B-cell non-Hodgkin's lymphoma.

Docetaxel 75 mg/m(2) is active and well tolerated in patients with metastatic or recurrent gastric cancer: a phase II trial

OBJECTIVE

The aim of the present study was to confirm the efficacy and tolerability of docetaxel 75 mg/m(2) in a population of Korean patients with advanced gastric cancer.

METHODS

Patients with metastatic or locally recurrent gastric cancer received docetaxel 75 mg/m(2) by intravenous infusion every 3 weeks. Objective response rate was the primary endpoint.

RESULTS

Forty-five patients were enrolled. Most showed adenocarcinomas of the gastric antrum and/or body of the stomach. All showed metastases and two-thirds retained the primary tumour. Forty-four patients received at least one docetaxel infusion ('treated' population), with 40 patients evaluable for response. A total of 159 cycles (median three cycles) were administered, with mean duration of treatment 10.9 weeks. The objective response rate in the treated population was 15.9% (17.5% in the per protocol population), with stable disease in 25.0% of patients and progressive disease in 50.0%. Grade 3-4 neutropenia occurred in 36 (81.8%) patients and 36.1% of cycles. However, febrile neutropenia occurred in only two (4.5%) patients and 1.3% of cycles. Grade 3 anorexia, experienced by two patients (4.5%) and during 1.9% of cycles, was the most frequent non-haematological adverse event possibly or probably related to docetaxel. No grade 4 non-haematological events occurred.

CONCLUSION

This study suggests that docetaxel 75 mg/m(2) is active in metastatic or locally recurrent adenocarcinoma with a low incidence of grade 3-4 adverse events. Docetaxel warrants further study in combination regimens for advanced gastric cancer.

Testican-1-mediated epithelial-mesenchymal transition signaling confers acquired resistance to lapatinib in HER2-positive gastric cancer

Human epidermal growth factor receptor 2 (HER2)-directed treatment using trastuzumab has shown clinical benefit in HER2-positive gastric cancer. Clinical trials using lapatinib in HER2-positive gastric cancer are also currently underway. As with other molecularly targeted agents, the emergence of acquired resistance to HER2-directed treatment is an imminent therapeutic problem for HER2-positive gastric cancer. In order to investigate the mechanisms of acquired resistance to HER2-directed treatment in gastric cancer, we generated lapatinib-resistant gastric cancer cell lines (SNU216 LR) in vitro by chronic exposure of a HER2-positive gastric cancer cell line (SNU216) to lapatinib. The resultant SNU216 LR cells were also resistant to gefitinib, cetuximab, trastuzumab, afatinib and dacomitinib. Interestingly, SNU216 LR cells displayed an epithelial-mesenchymal transition (EMT) phenotype and maintained the activation of MET, HER3, Stat3, Akt and mitogen-activated protein kinase signaling in the presence of lapatinib. Using gene expression arrays, we identified the upregulation of a variety of EMT-related genes and extracellular matrix molecules, such as Testican-1, in SNU216 LR cells. We showed that the inhibition of Testican-1 by small interfering RNA decreased Testican-1-induced, MET-dependent, downstream signaling, and restored sensitivity to lapatinib in these cells. Furthermore, treatment with XAV939 selectively inhibited β-catenin-mediated transcription and Testican-1-induced EMT signaling, leading to G1 arrest. Taken together, these data support the potential role of EMT in acquired resistance to HER2-directed treatment in HER2-positive gastric cancer, and provide insights into strategies for preventing and/or overcoming this resistance in patients.

Interleukin 12 gene therapy of cancer by peritumoral injection of transduced autologous fibroblasts: outcome of a phase I study

A phase I dose-escalation clinical trial of peritumoral injections of interleukin 12 (IL-12)-transduced autologous fibroblasts was performed in patients with disseminated cancer for whom effective treatment does not exist. The goals of this study were to assess the safety and toxicities as well as the efficacy, and ancillarily the immunomodulatory effects, of peritumoral IL-12 gene transfer. Primary dermal fibroblasts cultured from the patients were transduced with retroviral vector carrying human IL-12 genes (p35 and p40) as well as the neomycin phosphotransferase gene (TFG-hIL-12-Neo). Patients received four injections at intervals of 7 days. Nine patients were enrolled in this dose-escalation study, with secreted IL-12 doses ranging from 300 ng/24 hr for the first three patients to 1000, 3000, and 5000 ng/24 hr for two patients in each subsequent dosage level. Although a definite statement cannot be made, there appears to be perturbation of systemic immunity. Also, the locoregional effects mediated by tumor necrosis factor alpha (TNF-alpha) and CD8+ T cells were observed with tumor regression. Treatment-related adverse events were limited to mild to moderate pain at the injection site; clinically significant toxicities were not encountered. Transient but clear reductions of tumor sizes were observed at the injected sites in four of nine cases, and at noninjected distant sites in one melanoma patient. Hemorrhagic necrosis of tumors was observed in two melanoma patients. These data indicate that gene therapy by peritumoral injection of IL-12-producing autologous fibroblasts is feasible, and promising in patients with advanced cancer.

Soluble programmed death-ligand 1 (sPDL1) and neutrophil-to-lymphocyte ratio (NLR) predicts survival in advanced biliary tract cancer patients treated with palliative chemotherapy

Programmed death-ligand 1 (PD-L1) expression in tumor tissue is under investigation as a candidate biomarker in immuno-oncology dug development. The soluble form of PD-L1 (sPDL1) is suggested to have immunosuppressive activity. In this study, we measured the serum level of sPDL1 and evaluated its prognostic implication in biliary tract cancer (BTC). Blood was collected from 158 advanced BTC patients (68 intrahepatic cholangiocarcinoma, 56 gallbladder cancer, 22 extrahepatic cholangiocarcinoma and 12 ampulla of vater cancer) before initiation of palliative chemotherapy. Serum sPDL1 was measured using an enzyme-linked immunosorbent assay. Clinical data included neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII, neutrophil × platelet/lymphocyte). The patients were assigned to two cohorts (training and validation cohort) using a simple random sampling method to validate the cut-off value of each marker. Validation was performed using a twofold cross-validation method. Overall survival (OS) of all patients was 9.07 months (95% CI: 8.20-11.33). Median sPDL1 was 1.20 ng/mL (range 0.03-7.28, mean 1.50, SD 1.22). Median NLR, PLR and SII were 2.60, 142.85 and 584.93, respectively. Patients with high sPDL1 (≥0.94 ng/mL) showed worse OS than patients with low sPDL1 (7.93 vs. 14.10 months, HR 1.891 (1.35-2.65), p<0.001). In multivariate analysis, high sPDL1 and NLR were independent poor prognostic factors. In conclusion, serum sPDL1 can be measured and has significant role on the prognosis of advanced BTC patients treated with palliative chemotherapy.

Phase II study of oxaliplatin, 5-fluorouracil and leucovorin in previously platinum-treated patients with advanced gastric cancer

BACKGROUND

Oxaliplatin shows preclinical activity in many cancer cell lines that are resistant to cisplatin, and also has synergism with 5-fluorouracil (5-FU). We undertook this study to evaluate the efficacy and toxicities of a combined oxaliplatin, 5-FU and leucovorin (LV) continuous infusion regimen in patients with advanced gastric cancer who progressed during or after treatment with 5-FU and platinum compounds.

PATIENTS AND METHODS

Twenty-six patients with advanced gastric cancer, whose disease progressed while receiving, or after discontinuing, chemotherapy with a 5-FU and platinum regimen, were enrolled in this study. Treatment comprised oxaliplatin (85 mg/m2 on day 1) as a 2-h infusion followed by bolus 5-FU (400 mg/m2 on day 1), and 48-h infusion of 5-FU 2.4-3.0 g/m2 concurrently with LV 150 mg/m2. Cycles were repeated at 2-week intervals.

RESULTS

Of the 23 evaluable patients, there were six partial responses (response rate 26%). All responding patients were among those who entered into this trial immediately after failure of previous chemotherapy with 5-FU and cisplatin. The median time to progression was 4.3 months and the median overall survival was 7.3 months. The most common hematologic toxicity was grade 1-2 anemia in 39 cycles (39%). No grade 4 leukopenia or thrombocytopenia were observed. The most common non-hematologic toxicity was nausea/vomiting (33%). Peripheral neuropathy of grade 1 or 2 was noted (27%), but there was no grade 3 or 4 neurotoxicity.

CONCLUSIONS

This phase II study of oxaliplatin, 5-FU and LV continuous infusion showed activity in previously platinum-treated patients with advanced gastric cancer, with acceptable toxicities.

Transcriptional silencing of the DLC-1 tumor suppressor gene by epigenetic mechanism in gastric cancer cells

DLC-1 (deleted in liver cancer) gene is frequently deleted in hepatocellular carcinoma. However, little is known about the genetic status and the expression of this gene in gastric cancer. In this study, Northern and Southern analysis showed that seven of nine human gastric cancer cell lines did not express DLC-1 mRNA, but contained the DLC-1 gene. To identify the mechanism of the loss of DLC-1 mRNA expression in these cell lines, we investigated the methylation status of DLC-1 gene by using methylation-specific PCR (MSP) and Southern blot, and found that five of seven DLC-1 nonexpressing gastric cancer cell lines were methylated in the DLC-1 CpG island. Treatment with 5-aza-2'-deoxycytidine (5-Aza-dC) induced DLC-1 mRNA expression in the gastric cancer cell lines that have the methylated alleles. Studies using SNU-601 cell line with methylated DLC-1 alleles revealed that nearly all CpG sites within DLC-1 CpG island were methylated, and that the in vitro methylation of the DLC-1 promoter region is enough to repress DLC-1 mRNA expression, regardless of the presence of transcription factors capable of inducing this gene. In all, 29 of 97 (30%) primary gastric cancers were also shown to be methylated, demonstrating that methylation of the DLC-1 CpG island is not uncommon in gastric cancer. In addition, we demonstrated that DLC-1 mRNA expression was induced, and an increase in the level of acetylated H3 and H4 was detected by the treatment with trichostatin A (TSA) in two DLC-1 nonexpressing cell lines that have the unmethylated alleles. Taken together, the results of our study suggest that the transcriptional silencing of DLC-1, by epigenetic mechanism, may be involved in gastric carcinogenesis.

Histone deacetylase inhibitor enhances 5-fluorouracil cytotoxicity by down-regulating thymidylate synthase in human cancer cells

Thymidylate synthase (TS) overexpression is a key determinant of 5-fluorouracil (5-FU) resistance in human cancer cells. TS is also acutely up-regulated with 5-FU treatment, and, thus, novel strategies targeting TS down-regulation seem to be promising in terms of modulating 5-FU resistance. Here, we report that histone deacetylase inhibitors can reverse 5-FU resistance by down-regulating TS. By using cDNA microarrays and validation experiments, we found that trichostatin A reduced the expression of both TS mRNA and TS protein. Cotreatment with trichostatin A and cycloheximide restored TS mRNA expression, suggesting that TS mRNA is repressed through new protein synthesis. On the other hand, TS protein expression was significantly reduced by lower doses of trichostatin A (50 nmol/L). Mechanistically, TS protein was found to interact with heat shock protein (Hsp) complex, and trichostatin A treatment induced chaperonic Hsp90 acetylation and subsequently enhanced Hsp70 binding to TS, which led to the proteasomal degradation of TS protein. Of note, combined treatment with low-dose trichostatin A and 5-FU enhanced 5-FU-mediated cytotoxicity in 5-FU-resistant cancer cells in accordance with TS protein down-regulation. We conclude that a combinatorial approach using histone deacetylase inhibitors may be useful at overcoming 5-FU resistance.

Involvement of NF-kappaB and AP-1 in COX-2 upregulation by human papillomavirus 16 E5 oncoprotein

The human papillomavirus (HPV) E6 and E7 oncoproteins play important roles in cervical carcinogenesis through multiple mechanisms, including upregulation of cyclooxygenase-2 (COX-2), which has been shown to be involved in both carcinogenesis and cancer progression. To explore the role of E5 in cervical carcinogenesis, we herein investigated the effect of HPV 16 E5 on COX-2 expression. Our results revealed that E5 induced COX-2 expression through the epidermal growth factor receptor-signaling pathway, with nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) acting as critical factors in E5-induced COX-2 expression. NF-kappaB inhibition blocked COX-2 expression more potently than inhibition of AP-1. Our findings collectively suggest that the HPV 16 E5 oncoprotein mediates cervical carcinogenesis at least in part via upregulation of COX-2 expression through NF-kappaB and AP-1, with NF-kappaB playing a larger role.

High tumour islet macrophage infiltration correlates with improved patient survival but not with EGFR mutations, gene copy number or protein expression in resected non-small cell lung cancer

The purpose of this study was to investigate the prognostic value of tumour-associated macrophages with a focus on micro-anatomical localisation and determine whether molecular changes of the epidermal growth factor receptor (EGFR) are related to macrophage infiltration in resected non-small cell lung cancer (NSCLC). One hundred and forty-four patients were included in this study. Immunohistochemistry was used to identify CD68+ macrophages in the tumour islet and surrounding stroma. Epidermal growth factor receptor mutations were studied by direct sequencing. The EGFR gene copy number and protein expression were analysed by fluorescence in situ hybridisation and immunohistochemistry. Patients with a high tumour islet macrophage density survived longer than did the patient with a low tumour islet macrophage density (5-year overall survival rate was 63.9 vs 38.9%, P=0.0002). A multivariate Cox proportional hazard analysis revealed that the tumour islet macrophage count was an independent prognostic factor for survival (hazard ratio 0.471, 95% confidence interval 0.300-0.740). However, EGFR mutations, gene copy number, and protein expression were not related to the macrophage infiltration. In conclusion, tumour islet macrophage infiltration was identified as a strong favourable independent prognostic marker for survival but not correlated with the molecular changes of the EGFR in patients with resected NSCLC.

Lapatinib, a dual EGFR and HER2 tyrosine kinase inhibitor, downregulates thymidylate synthase by inhibiting the nuclear translocation of EGFR and HER2

BACKGROUND

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) has been shown to exert a synergistic antitumor effect when combined with fluoropyrimidine. This synergy may be attributable to the downregulation of thymidylate synthase (TS), which is frequently overexpressed in fluoropyrimidine-resistant cancer cells. However, the molecular mechanism underlying the downregulation of TS has yet to be clearly elucidated.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study, we demonstrate that lapatinib, a dual TKI of EGFR and HER2 downregulates TS via inhibition of the nuclear translocation of EGFR and HER2. From our cDNA microarray experiments, we determined that a variety of nucleotide synthesis-related genes, including TS, were downregulated with lapatinib, and this was apparent in HER2-amplified cells. Targeted and pharmacologic inhibition assays confirmed that the dual inhibition of EGFR and HER2 is required for the more effective reduction of TS as compared to what was observed with gefitinib or trasutuzumab alone. Additionally, we determined that co-transfected EGFR and HER2 activate the TS gene promoter more profoundly than do either EGFR or HER2 alone. The translocation of EGFR and HER2 into the nucleus and the subsequent activation of the TS promoter were inhibited by lapatinib.

CONCLUSIONS AND SIGNIFICANCE

These results demonstrate that lapatinib inhibits the nuclear translocation of EGFR and HER2 and downregulates TS, thus sensitizing cancer cells to fluoropyrimidine.

P2-purinergic receptor agonists inhibit the growth of androgen-independent prostate carcinoma cells

To develop a new approach to the treatment of advanced, hormone-refractory prostate cancer, the signal transductions regulating the growth of human androgen-independent prostate carcinoma cell lines were studied. Agonist-stimulated Ca2+ mobilization, a critical regulatory event in other secretory cell types, was studied as a means of identifying previously undescribed plasma membrane receptors that may transduce a growth inhibitory signal. In all of the cell lines tested, P2-purinergic receptor agonists, including ATP and certain hydrolysis-resistant adenine nucleotides, induced a rapid, transient increase in cytoplasmic free Ca2+ that was detectable at 50 to 100 nM ATP, was maximal at 100 microM ATP, and was inhibited approximately 50% by chelation of extracellular Ca2+. Within 8 s after addition, ATP stimulated accumulation of the polyphosphatidylinositol products inositol (1, 4, 5) trisphosphate, inositol (1, 3, 4) trisphosphate, and inositol tetrakisphosphate. In addition to stimulating phosphatidylinositol turnover and Ca2+ mobilization, ATP and hydrolysis-resistant ATP analogues induced greater than 90% inhibition of the growth of all lines tested. These data demonstrate that human androgen-independent prostate carcinoma cells express functional P2-purinergic receptors linked to phospholipase C, and that agonists of this receptor are markedly growth inhibitory, suggesting a novel therapeutic approach to this common adult neoplasm.

Class II histone deacetylases play pivotal roles in heat shock protein 90-mediated proteasomal degradation of vascular endothelial growth factor receptors

Vascular endothelial growth factor receptors (VEGFRs) perform pivotal roles in both tumor growth and angiogenesis. In this study, we report that histone deacetylase inhibitors (HDIs) induce a reduction in VEGFR1 and VEGFR2 protein expression via the inhibition of class II histone deacetylases (HDACs) in human cancer cell lines. After HDI treatment, VEGFR1 and VEGFR2 were shown to be downregulated in a proteasome-dependent manner. HDI treatment induced a reduction in the binding of heat shock protein (Hsp) 90 to VEGFR1 or VEGFR2, followed by an increase of the binding of Hsp70 to VEGFR1 or VEGFR2. However, we noted no remarkable changes in the binding of Hsp90/Hsp70 to VEGFR3. HDI treatment effectively inhibited the activities of HDAC6 and HDAC10. Furthermore, the knock-down of HDAC6 or HDAC10, which was accomplished via the siRNA transfection, induced depletion of VEGFR1 or VEGFR2 proteins. Overall, these results indicate that HDAC6 and HDAC10 play important roles in Hsp-mediated VEGFR regulation.

In vitro activities of native and designed peptide antibiotics against drug sensitive and resistant tumor cell lines

In order to develop peptide agents with reduced length and enhanced tumoricidal activity, we have designed gaegurin 6 (GGN6) derivatives through deletions and/or substitutions of amino acids. The deletion of hydrophobic amino terminal region completely abolished antitumor activity whereas the deletion of carboxy terminal region had little influence on antitumor activity. Antitumor activity of the PTP peptides did not correlate with antibacterial activity. PTP7, the most potent derivative, was found to have comparable antitumor activity to GGN6 in spite of reduced number of amino acids which is about half the size of gaegurin 6; furthermore, it showed little cytotoxicity on PBMCs and RBCs. GGN6 and PTP7 also showed equivalent cytotoxicity against drug sensitive (MCF-7) and multidrug-resistant cell lines (MCF-7/DOX). Plasma membrane blebbing and DNA fragmentation of peptide-treated tumor cells indicated that the peptides could induce apoptosis in tumor cells. These results suggest that GGN6 and its derivatives can be developed as new anticancer agents and may provide a new strategy for overcoming MDR which is a major problem in cancer therapy.

AKAP12/Gravin is inactivated by epigenetic mechanism in human gastric carcinoma and shows growth suppressor activity

AKAP12/Gravin, one of the A-kinase anchoring proteins (AKAPs), functions as a kinase scaffold protein and as a dynamic regulator of the beta2-adrenergic receptor complex. However, the biological role of AKAP12 in cancer development is not well understood. The AKAP12 gene encodes two major isoforms of 305 and 287 kDa (designated AKAP12A and AKAP12B, respectively, in this report). We found that these two isoforms are independently expressed and that they are probably under the control of two different promoters. Moreover, both isoforms were absent from the majority of human gastric cancer cells. The results from methylation-specific PCR (MSP) and bisulfite sequencing revealed that the 5' CpG islands of both AKAP12A and AKAP12B are frequently hypermethylated in gastric cancer cells. Treatment with DNA methyltransferase inhibitor and/or histone deacetylase inhibitor efficiently restored the expression of AKAP12 isoforms, confirming that DNA methylation is directly involved in the transcriptional silencing of AKAP12 in gastric cancer cells. Hypermethylation of AKAP12A CpG island was also detected in 56% (10 of 18) of primary gastric tumors. The restoration of AKAP12A in AKAP12-nonexpressing cells reduced colony formation and induced apoptotic cell death. In conclusion, our results suggest that AKAP12A may function as an important negative regulator of the survival pathway in human gastric cancer.

Increased MAPK activity and MKP-1 overexpression in human gastric adenocarcinoma

Mitogen-activated protein kinase (MAPK) has been known to play a critical role in the regulation of the carcinogenesis in human cancers. In an effort to understand the functional role of the MAPK in the carcinogenesis of human gastric tissues, we examined the changes of MAPK levels in human gastric adenocarcinoma. We found that increased MAPK activity was accompanied by overexpression of mitogen-activated protein kinase phosphatase-1 (MKP-1), suggesting that signaling pathways leading to the activation of MAPK and the induction of MKP-1 expression are associated with carcinogenesis of human gastric adenocarcinoma.

Epigenetic-based therapies in cancer: progress to date

Epigenetic gene silencing is a hallmark of cancer cells. Two important types of epigenetic changes are DNA methylation and histone modification. These modifications are catalysed by DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), resulting in chromatin structure changes and gene inactivation. Interestingly, inhibition of these enzymes is known to induce differentiation or apoptosis of cancer cells. Therefore, DNMTs and HDACs have become attractive therapeutic targets. In recent years, many different DNMT and HDAC inhibitors have been developed, and multiple molecular mechanisms through which these agents exert anti-cancer effects have been identified. While a large number of clinical trials are ongoing, hypomethylating agents and HDAC inhibitors seem to be promising for treating several types of cancer. Moreover, developing effective strategies of combining epigenetic therapy with conventional chemotherapy will be one of the major challenges in the future. We briefly review current advances in epigenetic therapies with a focus on recently reported clinical trials.

Trastuzumab Deruxtecan in Anti-Human Epidermal Growth Factor Receptor 2 Treatment-Naive Patients With Human Epidermal Growth Factor Receptor 2-Low Gastric or Gastroesophageal Junction Adenocarcinoma: Exploratory Cohort Results in a Phase II Trial

PURPOSE

To investigate efficacy and safety of trastuzumab deruxtecan (T-DXd) in human epidermal growth factor receptor 2 (HER2)-low gastric or gastroesophageal junction (GEJ) adenocarcinoma.

METHODS

Patients with locally advanced or metastatic HER2-low (cohort 1, immunohistochemistry 2+/in situ hybridization-negative; cohort 2, immunohistochemistry 1+) gastric/GEJ adenocarcinoma treated with at least two prior regimens, including fluoropyrimidine and platinum, but anti-HER2 therapy naive, received T-DXd 6.4 mg/kg intravenously once every 3 weeks. The primary end point was confirmed objective response rate by independent central review.

RESULTS

Among 21 patients enrolled in cohort 1 and 24 enrolled in cohort 2, 19 and 21 patients, respectively, had central HER2 confirmation, received T-DXd, and had measurable tumors at baseline. The confirmed objective response rate was 26.3% (95% CI, 9.1 to 51.2) from five partial responses in cohort 1 and 9.5% (95% CI, 1.2 to 30.4) from two partial responses in cohort 2. Thirteen patients (68.4%) in cohort 1 and 12 (60.0%) in cohort 2 experienced reduced tumor size. The median overall survival was 7.8 months (95% CI, 4.7 to nonevaluable) in cohort 1 and 8.5 months (95% CI, 4.3 to 10.9) in cohort 2; the median progression-free survival was 4.4 months (95% CI, 2.7 to 7.1) and 2.8 months (95% CI, 1.5 to 4.3), respectively. The most common grade ≥ 3 treatment-emergent adverse events in cohorts 1 and 2 were anemia (30.0% and 29.2%), decreased neutrophil count (25.0% and 29.2%), and decreased appetite (20.0% and 20.8%). Drug-related interstitial lung disease/pneumonitis occurred in one patient in each cohort (grade 1 or 2). No drug-related deaths occurred.

CONCLUSION

This study provides preliminary evidence that T-DXd has clinical activity in patients with heavily pretreated HER2-low gastric/GEJ adenocarcinoma.

Aggressiveness of cancer-care near the end-of-life in Korea

OBJECTIVE

The aim of this study was to examine the appropriateness of chemotherapy and care in Korean cancer patients near the end-of-life.

METHODS

We designed a retrospective cohort composed of patients diagnosed as having metastatic cancer and who received palliative chemotherapy at Seoul National University Hospital in 2002. Two hundred and ninety-eight patients who died of cancer were evaluated in terms of the appropriateness of the cancer-care they received, including chemotherapy.

RESULTS

Median duration of chemotherapy was 6.02 months compared with 8.67 months for median overall survival. The median period between last chemotherapy and death was 2.02 months. Of the 298 patients, 50.3% received chemotherapy during the last 2 months of life. Furthermore, 17 patients (5.7%) died within 2 weeks after receiving chemotherapy. The proportion who visited an emergency room (ER) more than once during the last months of life was 33.6%, and the average number of ER visits after a diagnosis of cancer was 1.72. Only 9.1% of patients were referred to a hospice consultation service and only 11.7% of patients agreed with written DNR.

CONCLUSIONS

Among patients who died of cancer, significant proportions were found to have received chemotherapy up to the end-of-life and to have visited ERs. Hospice referrals and discussions about DNR were not conducted well during the end-of-life period in Korea.

Cyclooxygenase-2 inhibits novel ginseng metabolite-mediated apoptosis

Recently, a novel intestinal bacterial metabolite of ginseng protopanaxadiol saponins, i.e., 20-O-(beta-D-glucopyranosyl)-20(S)-protopanaxadiol (IH-901), has been reported to induce apoptosis in a variety of cancer cells. Here we show a differential effect of IH-901 on several cell types. Exposure to IH-901 for 48 hours at a supposedly subapoptotic concentration of 40 mumol/L led to both apoptotic cell death and G1 arrest in Hep3B cells, but only resulted in G1 arrest in MDA-MB-231, Hs578T, and MKN28 cells. Additionally, the treatment of MDA-MB-231, but not of Hep3B, with IH-901 up-regulated cyclooxygenase-2 (COX-2) mRNA (2 hours) and protein (6 hours), and enhanced the production of prostaglandin E2. In MDA-MB-231 cells, IH-901 induced the sustained activation of extracellular signal-regulated kinase (ERK), whereas inhibition of mitogen-activated protein/ERK kinase blocked IH-901-mediated COX-2 induction and resulted in apoptosis, suggesting the involvement of an ERK-COX-2 pathway. Combined treatment with IH-901 and nonsteroidal anti-inflammatory drugs inhibited COX-2 enzyme and induced apoptosis in MDA-MB-231 and Hs578T cells. Adenovirus-mediated COX-2 small interfering RNAs also effectively inhibited COX-2 protein expression and enhanced IH-901-mediated apoptosis without inhibiting ERK 1/2 phosphorylation, thus providing direct evidence that COX-2 is an antiapoptotic molecule. Moreover, IH-901-mediated G1 arrest resulted from an increase in p27Kip1 mRNA and protein expression followed by a decrease in CDK2 kinase activity that was concurrent with the hypophosphorylation of Rb and p130. In conclusion, IH-901 induced both G1 arrest and apoptosis, and this apoptosis could be inhibited by COX-2 induction.

Role of postoperative radiotherapy in the management of extrahepatic bile duct cancer

PURPOSE

To analyze the outcome of postoperative radiotherapy (RT) or chemoradiation for patients with extrahepatic bile duct cancer who had undergone either curative or palliative surgery, and to identify the prognostic factors for these patients.

METHODS AND MATERIALS

Between March 1982 and December 1994, 91 patients with extrahepatic bile duct cancer underwent RT at the Department of Therapeutic Radiology, Seoul National University Hospital. Of these patients, 84 were included in this retrospective study. The male/female ratio was 3.7:1 (66 men and 18 women). The median age of the patients was 58 years (range 33-76). Gross total surgical resection was performed in 72 patients, with pathologically negative margins in 47 and microscopically positive margins in 25. Twelve patients underwent surgical exploration and biopsy or subtotal resection with palliative bypass procedures. All the patients received >40 Gy of external beam RT after surgery. Concurrent 5-fluorouracil was administered during external beam RT in 71 patients, and maintenance chemotherapy was performed in 61 patients after RT completion. The minimal follow-up of the survivors was 14 months, and the median follow-up period for all the patients was 23 months (range 2-75).

RESULTS

The overall 2- and 5-year survival rate was 52% and 31%, respectively. The 2- and 5-year disease-free survival rate was 48% and 26%, respectively. On univariate analysis using the Kaplan-Meier product limit method, the use of chemotherapy, performance status, N stage, size of residual tumor, stage, and tumor location were significant prognostic factors. However, on multivariate analysis using Cox's proportional hazard model, N stage (N0 vs. N1 and N2, p = 0.02) was the only significant prognostic factor.

CONCLUSION

Long-term survival can be expected in patients with extrahepatic bile duct cancer who undergo radical surgery and postoperative chemoradiation. Regional lymph node metastasis is a poor prognostic factor for these patients.

Mucoepidermoid carcinoma of lung: potential target of EGFR-directed treatment

Mucoepidermoid carcinoma (MEC) of lung is a rare malignancy of lung which originates from minor salivary glands of tracheobronchial tree. EGFR targeted therapy by inhibition of EGFR activation with the specific tyrosine kinase inhibitors (TKIs) has shown meaningful anti-tumor activity in patients with EGFR TK mutation and/or amplification, or in patients with adenocarcinoma. In the present study, we find that MEC has EGFR mutation in 40% (2 out of 5) of cases, and all mutations are L858R mutation. In addition, we also observed that a MEC patient well-responded to EGFR TKI in the absence of EGFR mutation or amplification. These data indicate for the first time that MEC of lung is another potential target of EGFR inhibitor, and more extended clinical investigation is warranted.

Identification and characterization of a novel cancer/testis antigen gene CAGE

We applied serological analysis of cDNA expression library technique to identify cancer-associated genes. We screened cDNA expression libraries of human testis and gastric cancer cell lines with sera of patients with gastric cancers. We identified a gene whose expression is testis-specific among normal tissues. We cloned and characterized this novel gene. It contains D-E-A-D box domain and encodes a putative protein of 630 amino acids with possible helicase activity. It showed wide expression in various cancer tissues and cancer cell lines. The corresponding gene was named cancer-associated gene (CAGE). PCR of human x hamster Radiation Hybrids showed localization of CAGE on the human chromosome Xp22. Transient transfection of CAGE showed predominantly nuclear localization. Both Western blot and plaque assay indicated seroreactivity of CAGE protein. We found that demethylation played a role in the activation of CAGE in some cancer cell lines that do not express it. Cell synchronization experiments showed that the expression of CAGE was related with cell cycle. This suggests that CAGE might play a role in cellular proliferation. Because CAGE is expressed in a variety of cancers but not in normal tissues except testis, this gene can be a target of antitumor immunotherapy.

RON (MST1R) is a novel prognostic marker and therapeutic target for gastroesophageal adenocarcinoma

RON (MST1R) is one of two members of the MET receptor tyrosine kinase family, along with parent receptor MET. RON has a putative role in several cancers, but its expression and function is poorly characterized in gastroesophageal adenocarcinoma. A recognized functional role of MET tyrosine kinase in gastroesophageal cancer has led to early phase clinical trials using MET inhibitors, with unimpressive results. Therefore, the role of RON in gastroesophageal cancer, as well as its role in cooperative signaling with MET and as a mechanism of resistance to MET inhibition, was studied in gastroesophageal tissues and cell lines. By IHC, RON was highly over-expressed in 74% of gastroesophageal samples (n=94), and over-expression was prognostic of poor survival (p=0.008); RON and MET co-expression occurred in 43% of samples and was prognostic of worst survival (p=0.03). High MST1R gene copy number by quantitative polymerase chain reaction, and confirmed by fluorescence in situ hybridization and/or array comparative genomic hybridization, was seen in 35.5% (16/45) of cases. High MST1R gene copy number correlated with poor survival (p=0.01), and was associated with high MET and ERBB2 gene copy number. A novel somatic MST1R juxtamembrane mutation R1018G was found in 11% of samples. RON signaling was functional in cell lines, activating downstream effector STAT3, and resulted in increased viability over controls. RON and MET co-stimulation assays led to enhanced malignant phenotypes over stimulation of either receptor alone. Growth inhibition as evidenced by viability and apoptosis assays was optimal using novel blocking monoclonal antibodies to both RON and MET, versus either alone. SU11274, a classic MET small molecule tyrosine kinase inhibitor, blocked signaling of both receptors, and proved synergistic when combined with STAT3 inhibition (combination index < 1). These preclinical studies define RON as an important novel prognostic marker and therapeutic target for gastroesophageal cancer warranting further investigation.

ERCC1 expression by immunohistochemistry and EGFR mutations in resected non-small cell lung cancer

Expression of excision repair cross-complementation group 1 (ERCC1) is important for resistance to platinum agents. Mutations of epidermal growth factor receptor (EGFR) are related to the responsiveness to tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC). This study was performed to determine if ERCC1 expression and EGFR are related to the prognosis of resected NSCLC, and to determine if ERCC1 expression and EGFR mutations are related. We used immunohistochemistry (IHC) to evaluate ERCC1 expression in tumors from 130 patients with curatively resected NSCLC. The median H-score was used as a cut-off for ERCC1 IHC. EGFR mutations were analyzed in exons 18, 19 and 21. ERCC1 expression was detected in tumors from 80 patients (61.5%). ERCC1 was expressed more frequently in smokers and in squamous cell carcinomas. Patients with a positive ERCC1 expression survived longer than ERCC1-negative patients (median overall survival 7.6 years for ERCC1-positive vs. 4.0 years for ERCC1-negative, P=0.046). Subsequent multivariate analysis suggested that ERCC1 expression is an independent prognostic marker of longer survival (hazard ratio: 0.598, 95% confidence interval: 0.357-1.001). EGFR mutations were found in 25 patients (19.2%) but did not affect overall survival. Interestingly, EGFR mutations were more frequent in ERCC1-negative tumors (12.5% in ERCC1-positive vs. 30% in ERCC1-negative tumors, P=0.014). In conclusion, ERCC1 expression was identified as a positive prognostic marker in resected NSCLC. In addition, EGFR mutations were more frequently found in ERCC1-negative tumors.