[A case of primary lung metastatic pancreatic tumor resected following chemoradiotherapy].

We observed a case of pancreatic metastasis of lung cancer being resected following chemoradiotherapy and reported with a review of the literature. The patient was a 60-year-old man and previously underwent an upper lobectomy of the right lung for the primary lesion and chemoradiotherapy for the metastatic lesion in the lower lobe of the right lung. During the follow-up period, positron emission tomography-computed tomography scan revealed a tumor in the pancreatic body, which was a hyperechoic mass on endoscopic ultrasonography (EUS) and hypervascularity on Sonazoid angiography. Fine needle aspiration cytology under EUS revealed dense growth of tumor cells with increased nuclear chromatin, markedly atypical nuclei, and eosinophilic sporangia. Immunostaining showed CK7 (+), CK20 (-), TTF-1 (+), and napsin A (+). He was diagnosed with pancreatic metastasis of lung cancer, underwent preoperative chemoradiotherapy followed by distal pancreatectomy and splenectomy, and discharged without perioperative complications. The right lower lobe metastasis of lung cancer was detected during an outpatient visit following chemoradiotherapy. However, he was found rectal cancer and considered a scheduled surgery. Forty-two months postoperatively, he was found dead at home;the cause of death was shock due to extreme dehydration.

Enhanced G1 arrest and apoptosis via MDM4/MDM2 double knockdown and MEK inhibition in wild-type TP53 colon and gastric cancer cells with aberrant KRAS signaling.

Murine double minute homolog 2 (MDM2) is an oncoprotein that induces p53 degradation via ubiquitin-ligase activity. MDM4 cooperates with MDM2-mediated p53 degradation, directly inhibiting p53 transcription by binding to its transactivation domain. Our previous study reported that the simultaneous inhibition of MDM2 and MDM4 using nutlin-3 (an inhibitor of the MDM2-p53 interaction) and chimeric small interfering RNA with DNA-substituted seed arms (named chiMDM2 and chiMDM4) more potently activated p53 than the MDM2 or MDM4 inhibitor alone and synergistically augmented antitumor effects in various types of cancer cells with the wild-type (wt) TP53. Recently, the synergism of MDM2 and mitogen-activated protein kinase kinase (MEK) inhibitors has been demonstrated in wt TP53 colorectal and non-small cell lung cancer cells harboring mutant-type (mt) KRAS. The current study examined whether chiMDM4 augmented the synergistic antitumor effects of MDM2 and MEK inhibition using chiMDM2 or nutlin-3 and trametinib, respectively. ChiMDM2 and trametinib used in combination demonstrated a synergistic antitumor activity in HCT116 and LoVo colon cancer cells, and SNU-1 gastric cancer cells harboring wt TP53 and mt KRAS. Furthermore, chiMDM4 synergistically enhanced this combinational effect. Similar results were observed when nutlin-3 was used instead of chiMDM2. MDM4/MDM2 double knockdown combined with trametinib treatment enhanced G1 arrest and apoptosis induction. This was associated with the accumulation of p53, suppression of phosphorylated-extracellular signal-regulated kinase 2, inhibition of retinoblastoma phosphorylation, suppression of E2F1-activated proteins, and potent activation of pro-apoptotic proteins, such as Fas and p53 upregulated modulator of apoptosis. The results inidcated that the triple inhibition of MDM4, MDM2 and MEK exerted a potent antitumor effect in wt TP53 colon and gastric cancer cells with mt KRAS. Simultaneous activation of p53 and inhibition of aberrant KRAS signaling may be a rational treatment strategy for gastrointestinal tumors.

MDM4 as a Prognostic Factor for Patients With Gastric Cancer With Low Expression of p53.

BACKGROUND/AIM: The oncoproteins murine double minute (MDM) 2 and MDM4 inactivate tumor-suppressor protein p53. Their mutual relationship with the prognosis of gastric cancer (GC) remains unknown. PATIENTS AND METHODS: Expression of MDM2, MDM4, and p53 in tumors of 241 patients with GC were evaluated immunohistochemically. Effects of overexpression of MDM4 on tumor-growth properties and sensitivity to cytotoxic drugs were investigated using NUGC4 human GC cell line. RESULTS: High expression of p53 was associated with poor overall survival in the whole population. Among 173 patients with low expression of p53 (implying nonmutation), high expression of MDM4 was an independent factor of poor prognosis in both stage I-III and IV, but of MDM2 was not. MDM4-transduced NUGC4 cells formed twice as many colonies and had a higher 50% inhibitory concentration for 5-fluorouracil and oxaliplatin than did the control cells. CONCLUSION: MDM4 expression is a factor conferring poor prognosis in patients with GC with low expression of p53 and may confer drug resistance.

Augmented antitumor activity of 5-fluorouracil by double knockdown of MDM4 and MDM2 in colon and gastric cancer cells.

Inactivation of the TP53 tumor suppressor gene is essential during cancer development and progression. Mutations of TP53 are often missense and occur in various human cancers. In some fraction of wild-type (wt) TP53 tumors, p53 is inactivated by upregulated murine double minute homolog 2 (MDM2) and MDM4. We previously reported that simultaneous knockdown of MDM4 and MDM2 using synthetic DNA-modified siRNAs revived p53 activity and synergistically inhibited in vitro cell growth in cancer cells with wt TP53 and high MDM4 expression (wtTP53/highMDM4). In the present study, MDM4/MDM2 double knockdown with the siRNAs enhanced 5-fluorouracil (5-FU)-induced p53 activation, arrested the cell cycle at G1 phase, and potentiated the antitumor effect of 5-FU in wtTP53/highMDM4 human colon (HCT116 and LoVo) and gastric (SNU-1 and NUGC-4) cancer cells. Exposure to 5-FU alone induced MDM2 as well as p21 and PUMA by p53 activation. As p53-MDM2 forms a negative feedback loop, enhancement of the antitumor effect of 5-FU by MDM4/MDM2 double knockdown could be attributed to blocking of the feedback mechanism in addition to direct suppression of these p53 antagonists. Intratumor injection of the MDM4/MDM2 siRNAs suppressed in vivo tumor growth and boosted the antitumor effect of 5-FU in an athymic mouse xenograft model using HCT116 cells. These results suggest that a combination of MDM4/MDM2 knockdown and conventional cytotoxic drugs could be a promising treatment strategy for wtTP53/highMDM4 gastrointestinal cancers.

Efficacy of adjuvant chemotherapy after resection of pulmonary metastasis from colorectal cancer: a propensity score-matched analysis.

BACKGROUND: Pulmonary metastases from colorectal cancer are resected due to the favourable 5-year overall survival rates of 30-60% reported in many studies. However, the efficacy of subsequent adjuvant chemotherapy remains unclear. PATIENT AND METHODS: We retrospectively collected clinical data of 1237 patients who underwent surgical resection of pulmonary metastasis from colorectal cancer at 46 Japanese institutions between 2004 and 2008. Patients with non-curative resection, pre-operative chemotherapy, extra-thoracic metastasis, complications after surgery, and inadequate data were excluded. Then, a 1:1 propensity score nearest-neighbour matching between patients with and without adjuvant chemotherapy was performed, considering relevant co-variables, and survival of patients between groups was compared. RESULTS: Data of 524 patients (surgery alone, 269 patients; surgery with adjuvant chemotherapy, 255 patients) were used for matching. From each group, 192 patients with similar background characteristics between groups were selected. Adjuvant chemotherapies included fluoropyrimidine alone (71%), an oxaliplatin-containing regimen (23%), or an irinotecan-containing regimen (6%). In the surgery alone and adjuvant chemotherapy groups, 5-year overall survival rates were 68% and 69%, and 5-year disease-free survival rates were 40% and 34%, respectively. There were no significant differences between the two groups in terms of overall survival (hazard ratio [HR]: 1.00, 95% confidence interval [CI]: 0.69-1.45, P = 1.00) and disease-free survival (HR: 1.07, 95% CI: 0.82-1.39, P = 0.62). CONCLUSIONS: Adjuvant chemotherapy after curative resection of lung-limited metastasis from colorectal cancer did not show a survival benefit in the propensity score-matched analysis and should not be recommended without further clinical trials.

Successful Treatment with Modified FOLFOX6 and Panitumumab in a Cecal Cancer Patient Undergoing Hemodialysis.

Combination chemotherapy of mFOLFOX6 (5-fluorouracil, leucovorin, and oxaliplatin) plus panitumumab, a fully human monoclonal antibody against epidermal growth factor receptor (EGFR), is one of the standard treatments for metastatic colorectal cancer (mCRC) without KRAS mutation. A few reports suggested no need of dose adjustment of cetuximab, a similar chimeric anti-EGFR antibody, in patients with renal impairment. However, panitumumab combined with cytotoxic drugs for hemodialysis patients has not been reported. We herein report a case of a hemodialysis mCRC patient successfully treated with mFOLFOX6 and panitumumab combination therapy.

Phase I study of gemcitabine, cisplatin, and S-1 combination therapy for patients with untreated advanced biliary tract cancer.

BACKGROUND: To develop a triplet regimen containing gemcitabine, cisplatin, and S-1 (GPS), we assessed the recommended dose for patients with untreated advanced biliary tract cancer in this phase I study. METHODS: Dose-limiting toxicities (DLTs) were evaluated for the following two dose levels: gemcitabine (1000 mg/m(2) for level 1 and 1200 mg/m(2) for level 2 on day 1), cisplatin (30 mg/m(2) fixed dose on day 1), and S-1 (40-60 mg/day fixed dose twice a day for 7 days), every 2 weeks until progression. DLTs for each level were evaluated in six or more patients during the first two cycles. RESULTS: A total of 18 patients were enrolled and 16 patients were evaluated. DLTs at level 1 were observed in two of 10 patients. At level 2, a DLT was observed in one of six patients. The main grade 3 or 4 treatment-related adverse events were neutropenia and leukopenia, and a few non-hematological toxicities were observed. Among 14 patients with measurable lesions, the best response rate was 50%. CONCLUSIONS: GPS with a relative dose intensity corresponding to 90% of the standard gemcitabine plus cisplatin regimen could be administered safely, and showed preliminary antitumor activity. Survival benefits will be studied subsequently.

[A retrospective analysis of cetuximab or panitumumab monotherapy for KRAS wild-type metastatic colorectal cancer in clinical practice].

We performed a retrospective study on the use of cetuximab or panitumumab alone in patients with KRAS wild-type metastatic colorectal cancer between November 2008 and February 2012. Twenty-two patients were analyzed and classified as PS 0/1 (good PS group)and PS 2/3/4 (poor PS group)with 11 patients in each group. The response rate, disease control rate, median progression-free survival, and median overall survival were 9%, 73%, 5.1 months (95%confidence interval[CI]: 1.5-8.7), and 16 months (95% CI: 8.8-24), respectively, in the good PS group, and the corresponding values in the poor PS group were 0%, 18%, 0.7 months (95% CI: 0.3-1.0), and 1.5 months (95% CI: 0.7-2.4). Grade 3 or 4 adverse events were skin toxicities (2 patients with grade 3 toxicities), panitumumab-related interstitial lung disease (1 patient with grade 4 toxicity), and cetuximab infusion-related reaction (1 patient with grade 4 toxicity). No treatment-related deaths were observed. In conclusion, the efficacy and safety of cetuximab or panitumumab monotherapy in patients with a good PS in our study were similar to those reported in previous clinical trials, whereas patients with a poor PS showed poorer outcomes.

[A case of malignant peritoneal mesothelioma with the epithelioid histological type, successfully treated with pemetrexed plus cisplatin].

A 45-year-old man presented with severe abdominal distention with massive ascites due to a diffusely disseminated peritoneal tumor. A core needle biopsy specimen was obtained from the peritoneal lesion. Histological diagnosis was epithelioid type mesothelioma. He did not choose to receive chemotherapy. For 2.5 years, he went without medical intervention, and his disease gradually progressed, leading to a worsening of his symptoms. The patient then chose to be treated with combination chemotherapy of cisplatin and pemetrexed, followed by pemetrexed alone. There was remarkable tumor shrinkage and his symptoms improved. These effects have been sustained for two years after the initial chemotherapy. Chemotherapy appears to have contributed to survival prolongation for this patient. This case exemplifies the fact that malignant peritoneal mesothelioma may progress slowly when fits with some good prognostic factors, and it is important to consider the prognostic factors.