Dimensionality reduction for deep learning in infrared microscopy: a comparative computational survey.

While infrared microscopy provides molecular information at spatial resolution in a label-free manner, exploiting both spatial and molecular information for classifying the disease status of tissue samples constitutes a major challenge. One strategy to mitigate this problem is to embed high-dimensional pixel spectra in lower dimensions, aiming to preserve molecular information in a more compact manner, which reduces the amount of data and promises to make subsequent disease classification more accessible for machine learning procedures. In this study, we compare several dimensionality reduction approaches and their effect on identifying cancer in the context of a colon carcinoma study. We observe surprisingly small differences between convolutional neural networks trained on dimensionality reduced spectra compared to utilizing full spectra, indicating a clear tendency of the convolutional networks to focus on spatial rather than spectral information for classifying disease status.

DAXX, ATRX, and MSI in PanNET and Their Metastases: Correlation with Histopathological Data and Prognosis.

INTRODUCTION: Studies on pancreatic neuroendocrine tumors (PanNETs) regarding loss of ATRX, DAXX, or frequency of microsatellite instability (MSI) show inconclusive results. So far, data on corresponding metastaseshave not been published. METHODS: We performed immunohistochemistry (IHC) of ATRX, DAXX, MSH2, MSH6, MLH1, and PMS2 on 74 PanNETs and 19 metastases. ATRX- and DAXX-negative PanNETs were further sequenced for mutations. We used polymerase chain reaction for MSI on cases with IHC loss of MSH2, MSH6, MLH1, and PMS2. RESULTS: Immunohistochemical loss of DAXX and ATRX was observed in 8/74 (11%) and 6/74 (8%) PanNETs. Loss of DAXX immunoreactivity was statistically associated with higher tumor grade and showed a tendency toward a decreased overall survival. Sequencing of DAXX- (7/11 [64%]) and ATRX-negative (5/11 [45%]) PanNETs revealed a mutation in 6/7 (86%) and 2/5 (40%). The specificity of immunohistochemical loss of DAXX and ATRX for mutation was 80% and 67%, respectively. The expression status of DAXX compared to primary tumor differs in 2/12 (17%) lymph node metastases. We further identified 3/74 (4%) tumors as MSI, associated with a poor prognosis. DISCUSSION/CONCLUSION: Our study supports the hypothesis that a loss of DAXX immunoreactivity can identify a more aggressive subtype of PanNET with high confidence, while ATRX loss is a weaker indicator. Our results also strengthen the role of DAXX immunolabeling as a prognostic marker. We could show that ATRX might be less suitable as a surrogate for sequencing. Our results indicate that IHC of DAXX and ATRX may identify PanNET subtypes as targets for more aggressive therapy.

Maintenance Olaparib for Germline BRCA-Mutated Metastatic Pancreatic Cancer.

BACKGROUND: Patients with a germline BRCA1 or BRCA2 mutation make up a small subgroup of those with metastatic pancreatic cancer. The poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor olaparib has had antitumor activity in this population. METHODS: We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to evaluate the efficacy of olaparib as maintenance therapy in patients who had a germline BRCA1 or BRCA2 mutation and metastatic pancreatic cancer and disease that had not progressed during first-line platinum-based chemotherapy. Patients were randomly assigned, in a 3:2 ratio, to receive maintenance olaparib tablets (300 mg twice daily) or placebo. The primary end point was progression-free survival, which was assessed by blinded independent central review. RESULTS: Of the 3315 patients who underwent screening, 154 underwent randomization and were assigned to a trial intervention (92 to receive olaparib and 62 to receive placebo). The median progression-free survival was significantly longer in the olaparib group than in the placebo group (7.4 months vs. 3.8 months; hazard ratio for disease progression or death, 0.53; 95% confidence interval [CI], 0.35 to 0.82; P = 0.004). An interim analysis of overall survival, at a data maturity of 46%, showed no difference between the olaparib and placebo groups (median, 18.9 months vs. 18.1 months; hazard ratio for death, 0.91; 95% CI, 0.56 to 1.46; P = 0.68). There was no significant between-group difference in health-related quality of life, as indicated by the overall change from baseline in the global quality-of-life score (on a 100-point scale, with higher scores indicating better quality of life) based on the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (between-group difference, -2.47 points; 95% CI, -7.27 to 2.33). The incidence of grade 3 or higher adverse events was 40% in the olaparib group and 23% in the placebo group (between-group difference, 16 percentage points; 95% CI, -0.02 to 31); 5% and 2% of the patients, respectively, discontinued the trial intervention because of an adverse event. CONCLUSIONS: Among patients with a germline BRCA mutation and metastatic pancreatic cancer, progression-free survival was longer with maintenance olaparib than with placebo. (Funded by AstraZeneca and others; POLO ClinicalTrials.gov number, NCT02184195.).

Complete mesocolic excision for right colonic cancer: prospective multicentre study.

BACKGROUND: Complete mesocolic excision (CME) for right colonic cancer is a more complex operation than standard right hemicolectomy but evidence to support its routine use is still limited. This prospective multicentre study evaluated the effect of CME on long-term survival in colorectal cancer centres in Germany (RESECTAT trial). The primary hypothesis was that 5-year disease-free survival would be higher after CME than non-CME surgery. A secondary hypothesis was that there would be improved survival of patients with a mesenteric area greater than 15 000 mm2. METHODS: Centres were asked to continue their current surgical practices. The surgery was classified as CME if the superior mesenteric vein was dissected; otherwise it was assumed that no CME had been performed. All specimens were shipped to one institution for pathological analysis and documentation. Clinical data were recorded in an established registry for quality assurance. The primary endpoint was 5-year overall survival for stages I-III. Multivariable adjustment for group allocation was planned. Using a primary hypothesis of an increase in disease-free survival from 60 to 70 per cent, a sample size of 662 patients was calculated with a 50 per cent anticipated drop-out rate. RESULTS: A total of 1004 patients from 53 centres were recruited for the final analysis (496 CME, 508 no CME). Most operations (88.4 per cent) were done by an open approach. Anastomotic leak occurred in 3.4 per cent in the CME and 1.8 per cent in the non-CME group. There were slightly more lymph nodes found in CME than non-CME specimens (mean 55.6 and 50.4 respectively). Positive central mesenteric nodes were detected more in non-CME than CME specimens (5.9 versus 4.0 per cent). One-fifth of patients had died at the time of study with recorded recurrences (63, 6.3 per cent), too few to calculate disease-free survival (the original primary outcome), so overall survival (not disease-specific) results are presented. Short-term and overall survival were similar in the CME and non-CME groups. Adjusted Cox regression indicated a possible benefit for overall survival with CME in stage III disease (HR 0.52, 95 per cent c.i. 0.31 to 0.85; P = 0.010) but less so for disease-free survival (HR 0.66; P = 0.068). The secondary outcome (15 000 mm2 mesenteric size) did not influence survival at any stage (removal of more mesentery did not alter survival). CONCLUSION: No general benefit of CME could be established. The observation of better overall survival in stage III on unplanned exploratory analysis is of uncertain significance.

Serial Circulating Tumor DNA Mutational Status in Patients with KRAS-Mutant Metastatic Colorectal Cancer from the Phase 3 AIO KRK0207 Trial.

BACKGROUND: We assessed the usefulness of circulating tumor DNA (ctDNA) pre- or post-treatment initiation for outcome prediction and treatment monitoring in metastatic colorectal cancer (mCRC). METHODS: Droplet digital PCR was used to measure absolute mutant V-Ki-ras2 Kirsten rat sarcoma viral oncogene ((mut)KRAS) ctDNA concentrations in 214 healthy controls (plasma and sera) and in 151 tissue-based mutKRAS positive patients with mCRC from the prospective multicenter phase 3 trial AIO KRK0207. Serial mutKRAS ctDNA was analyzed prior to and 2-3 weeks after first-line chemotherapy initiation with fluoropyrimidine, oxaliplatin, and bevacizumab in patients with mCRC and correlated with clinical parameters. RESULTS: mut KRAS ctDNA was detected in 74.8% (113/151) of patients at baseline and in 59.6% (90/151) at follow-up. mutKRAS ctDNA at baseline and follow-up was associated with poor overall survival (OS) (hazard ratio [HR] =1.88, 95% confidence interval [CI] 1.20-2.95; HR = 2.15, 95% CI 1.47-3.15) and progression-free survival (PFS) (HR = 2.53, 95% CI 1.44-4.46; HR = 1.90, 95% CI 1.23-2.95), respectively. mutKRAS ctDNA clearance at follow-up conferred better disease control (P = 0.0075), better OS (log-rank P = 0.0018), and PFS (log-rank P = 0.0018). Measurable positive mutKRAS ctDNA at follow-up was the strongest and most significant independent prognostic factor on OS in multivariable analysis (HR = 2.31, 95% CI 1.40-3.25). CONCLUSIONS: Serial analysis of circulating mutKRAS concentrations in mCRC has prognostic value. Post treatment mutKRAS concentrations 2 weeks after treatment initiation were associated with therapeutic response in multivariable analysis and may be an early response predictor in patients receiving first-line combination chemotherapy. CLINICALTRIALSGOV IDENTIFIER: NCT00973609.

Current status of immunotherapy in gastrointestinal malignancies.

Gastrointestinal (GI) malignant neoplasms have a high global incidence and a huge impact on cancer-associated mortality. In the past years, excitement was growing among oncologists and patients alike for the use of immunotherapy, specifically immune checkpoint inhibitors. The approval of several PD-1/PD-L1 and CTLA-4 inhibitors radically changed the treatment landscape in many cancer types and established immune-oncology as a new treatment strategy against cancer. Despite major breakthrough reports, shortcomings of immune checkpoint inhibitors (ICI) have been observed, including primary and acquired treatment resistance, especially in patients receiving ICIs as a single treatment. Several immunotherapies for the treatment of GI tumors have recently emerged; however, checkpoint inhibition has not yet shown similar success in GI malignancies compared to other solid tumors. Various phase I-III trials focusing on immunotherapies for GI tumors have found only moderate to unsatisfactory objective response rates (ORR), ranging between 10 % and 25 %. In particular, negative studies have been reported in gastric and pancreatic cancer. Nevertheless, small subsets of cancers, such as DNA mismatch repair deficient (dMMR)/microsatellite instable (MSI) cancers, among others, seem to benefit from treatment with immune checkpoint inhibition. Routine testing for the rare molecular features that can predict response should be implemented in clinical routine for all GI tumors, and large scale clinical trials to identify predictive biomarkers are needed. This article will address the current use and evidence for immunotherapy in GI malignancies and future trends in this area for clinical practice.

High microsatellite instability (MSI-H) is associated with distinct clinical and molecular characteristics and an improved survival in early Colon cancer (CC); real world data from the AIO molecular registry Colopredict Plus.

Colorectal cancer is one of the leading malignancies and still accounts for almost 25 000 deaths in Germany each year. Although there is accumulating data on the molecular basis, treatment and clinical outcome of patients within clinical trials evidence from the real-world setting is mostly lacking. We started the molecular registry trial Colopredict Plus in 2013 to collect clinical and molecular data from a real-world cohort of patients with early colon cancer stage II and III in 70 German colon cancer centers focusing on the prognostic impact of high microsatellite instability. In this interim report, we characterize a clinical cohort of 2615 patients, of whom 1787 tissue probes were analyzed. Microsatellite status was assessed using immunhistochemistry and fragment length analysis, with a concordance of 91.4 %. These established histopathological methods are sensitive and cost-effective. The median age was 72 years, significantly higher compared to clinical trial populations, with a median Charlson Comorbidity Index of 3. The stage-dependent incidence of microsatellite instability was 23.7 % and was associated with female gender, BRAF-mutation, UICC stage II and localization in the right colon. Survival calculated in disease free, relapse free and overall survival significantly differed between MSI-H and MSS, in favor of MSI-H patients. Multivariate age-adjusted analyses of relapse-free survival, disease-free survival, and overall survival highlighted microsatellite instability as a robust and positive prognostic marker for early colon cancer independent of age.

[Prerequisites of magnetic resonance imaging for treatment planning in locally advanced rectal cancer - Interdisciplinary recommendations]. / Stellenwert und qualitative Voraussetzungen der Magnetresonanztomografie für die Therapieplanung beim lokal fortgeschrittenen Rektumkarzinom ­ Interdisziplinäre Empfehlungen.

For the purpose of indication and patient stratification of perioperative treatment of locally advanced rectal cancer, magnetic resonance imaging (MRI) has become indispensable. In this report, we describe the importance of MRI diagnostics and the qualitative conditions.

"I need to know what makes somebody tick ": Challenges and Strategies of Implementing Shared Decision-Making in Individualized Oncology.

BACKGROUND: Shared decision-making (SDM) has been advocated as an ethical framework for decision-making in cancer care. According to SDM, patients make decisions in light of their values and based on the available evidence. However, SDM is difficult to implement in cancer care. A lack of applicability in practice is often reported. This empirical-ethical study explores factors potentially relevant to current difficulties in translating the concept of SDM into clinical practice. METHODS: This study was conducted with nonparticipant observation of the decision-making process in patients with gastrointestinal cancers for whom the benefit of adjuvant chemotherapy was uncertain according to clinical guidelines. Triangulation of qualitative data analysis was conducted by means of semistructured interviews subsequent to the observation. Observation notes and interview transcripts were analyzed according to the principles of grounded theory. RESULTS: Deviating from the concept of SDM, oncologists initiated a process of eliciting values and medical information prior to conveying information. The purpose of this approach was to select and individualize information relevant to the treatment decision. In doing so, the oncologists observed used two strategies: "biographical communication" and a "metacommunicative approach." Both strategies could be shown to be effective or to fail depending on patients' characteristics such as their view of the physicians' role and the relevance of value-related information for medical decision-making. CONCLUSION: In contrast to the conceptual account of SDM, oncologists are in need of patient-related information prior to conveying information. Both strategies observed to elicit such information are in principle justifiable but need to be adapted in accordance with patient preferences and decision-making styles. IMPLICATIONS FOR PRACTICE: This study showed that knowledge of patients' values and preferences is very important to properly adapt the giving of medical information and to further the process of shared decision-making. Shared decision-making (SDM) trainings should consider different strategies of talking about values. The right strategy depends largely on the patient's preferences in communication. To be aware of the role of values in SDM and to be able to switch communicative strategies might prove to be of particular value. A more systematic evaluation of the patient's decision-making preferences as part of routine procedures in hospitals might help to reduce value-related barriers in communication.

Neoadjuvant plus adjuvant or only adjuvant nab-paclitaxel plus gemcitabine for resectable pancreatic cancer - the NEONAX trial (AIO-PAK-0313), a prospective, randomized, controlled, phase II study of the AIO pancreatic cancer group.

BACKGROUND: Even clearly resectable pancreatic cancer still has an unfavorable prognosis. Neoadjuvant or perioperative therapies might improve the prognosis of these patients. Thus, evaluation of perioperative chemotherapy in resectable pancreatic cancer in a prospective, randomized trial is warranted. A substantial improvement in overall survival of patients with metastatic pancreatic cancer with FOLFIRINOX and nab-paclitaxel/gemcitabine vs standard gemcitabine has been demonstrated in phase III-trials. Indeed nab-paclitaxel/gemcitabine has a more favorable toxicity profile compared to the FOLFIRINOX protocol and appears applicable in a perioperative setting. METHODS: NEONAX is an interventional, prospective, randomized, controlled, open label, two sided phase II study with an unconnected analysis of the results in both experimental arms against a fixed survival probability (38% at 18 months with adjuvant gemcitabine), NCT02047513. NEONAX will enroll 166 patients with resectable pancreatic ductal adenocarcinoma (≤ cT3, N0 or N1, cM0) in two arms: Arm A (perioperative arm): 2 cycles nab-paclitaxel (125 mg/m2)/gemcitabine (1000 mg/m2, d1, 8 and 15 of an 28 day-cycle) followed by tumor surgery followed by 4 cycles nab-paclitaxel/gemcitabine, Arm B (adjuvant arm): tumor surgery followed by 6 cycles nab-paclitaxel/gemcitabine. The randomization (1:1) is eminent to avoid allocation bias between the groups. Randomization is stratified for tumor stage (ct1/2 vs. cT3) and lymph node status (cN0 vs. cN1). Primary objective is disease free survival (DFS) at 18 months after randomization. Key secondary objectives are 3-year overall survival (OS) rate and DFS rate, progression during neoadjuvant therapy, R0 and R1 resection rate, quality of life and correlation of DFS, OS and tumor regression with pharmacogenomic markers, tumor biomarkers and molecular analyses (ctDNA, transcriptome, miRNA-arrays). In addition, circulating tumor-DNA will be analyzed in patients with the best and the worst responses to the neoadjuvant treatment. The study was initiated in March 2015 in 26 centers for pancreatic surgery in Germany. DISCUSSION: The NEONAX trial is an innovative study on resectable pancreatic cancer and currently one of the largest trials in this field of research. It addresses the question of the role of intensified perioperative treatment with nab-paclitaxel plus gemcitabine in resectable pancreatic cancers to improve disease-free survival and offers a unique potential for translational research. TRIAL REGISTRATION: ClinicalTrials.gov : NCT02047513, 08/13/2014.

[ASCO- and ESMO-update 2017 - highlights of the 53. meeting of the American Society of Clinical Oncology/ASCO 2017 and European Society for Medical Oncology/ESMO congress 2017]. / ASCO- und ESMO-Update 2017 ­ Neuigkeiten vom 53. Meeting der American Society of Clinical Oncology/ASCO 2017 und European Society for Medical Oncology/ESMO-Congress 2017.

At ASCO 2017, and subsequently the ESMO congress 2017, a number of studies were presented which, in part, may change the present standard of therapy in gastrointestinal oncology. The German FLOT4 trial established perioperative Docetaxel, Oxaliplatin and 5-Fluorouracil (5-FU) as the new treatment standard for resectable adenocarcinoma of the gastroesophageal junction and the stomach. In hepatocellular carcinoma (HCC), two large studies did not show a survival benefit for selective internal therapy (SIRT), so an increasing use of SIRT in HCC is not recommended. On the other hand, the multityrosinekinase inhibitor Lenvatinib seems to be a promising alternative to sorafenib in first line treatment of metastatic HCC. In early colon cancer-following the data from the large IDEA initiative-three months of capecitabine and oxaliplatin is recommended for low-risk stage III cancers (T1 - 3, N1), while in high-risk stage III cancers (T4 or N2) patients should still receive six months of oxaliplatin and a fluoropyrimidine. Aside from regular exercise, one study found that regular intake of tree nuts (at least 2 servings per week), may decrease the risk of recurrence. In first line metastatic colorectal cancer (mCRC), SIRT should not be applied, whereas in BRAF mutant cancers, the combination of irinotecan, cetuximab and vemurafenib seems to be a promising second line treatment option. In biliary tract cancer, after curative resection, six months of capecitabine is considered the new treatment standard. Finally, in pancreatic cancer, targeting the tumor stroma with pegylated hyaluronidase (PEGPH20) may be a new treatment option that needs to be proven in phase 3 studies.

Methylated free-circulating HPP1 DNA is an early response marker in patients with metastatic colorectal cancer.

Detection of methylated free-circulating DNA (mfcDNA) for hyperplastic polyposis 1 (HPP1) in blood is correlated with a poor prognosis for patients with metastatic colorectal cancers (mCRC). Here, we analyzed the plasma levels of HPP1 mfcDNA in mCRC patients treated with a combination therapy containing a fluoropyrimidine, oxaliplatin and bevacizumab to test whether HPP1 mfcDNA is a suitable prognostic and response biomarker. From 467 patients of the prospective clinical study AIO-KRK-0207, mfcDNA was isolated from plasma samples at different time points and bisulfite-treated mfcDNA was quantified using methylation specific PCR. About 337 of 467 patients had detectable levels for HPP1 mfcDNA before start of treatment. The detection was significantly correlated with poorer overall survival (OS) (HR = 1.86; 95%CI 1.37-2.53). About 2-3 weeks after the first administration of combination chemotherapy, HPP1 mfcDNA was reduced to non-detectable levels in 167 of 337 patients. These patients showed a better OS compared with patients with continued detection of HPP1 mfcDNA (HR HPP1(sample 1: pos/ sample 2: neg) vs. HPP1(neg/neg) = 1.41; 95%CI 1.00-2.01, HPP1(neg,pos/pos) vs. HPP1(neg/neg) = 2.60; 95%CI 1.86-3.64). Receiver operating characteristic analysis demonstrated that HPP1 mfcDNA discriminates well between patients who do (not) respond to therapy according to the radiological staging after 12 or 24 weeks (AUC = 0.77 or 0.71, respectively). Detection of HPP1 mfcDNA can be used as a prognostic marker and an early marker for response (as early as 3-4 weeks after start of treatment compared with radiological staging after 12 or 24 weeks) to identify patients who will likely benefit from a combination chemotherapy with bevacizumab.

Maintenance strategies after first-line oxaliplatin plus fluoropyrimidine plus bevacizumab for patients with metastatic colorectal cancer (AIO 0207): a randomised, non-inferiority, open-label, phase 3 trial.

BACKGROUND: The definition of a best maintenance strategy following combination chemotherapy plus bevacizumab in metastatic colorectal cancer is unclear. We investigated whether no continuation of therapy or bevacizumab alone are non-inferior to fluoropyrimidine plus bevacizumab, following induction treatment with a fluoropyrimidine plus oxaliplatin plus bevacizumab. METHODS: In this open-label, non-inferiority, randomised phase 3 trial, we included patients aged 18 years or older with histologically confirmed, previously untreated metastatic colorectal cancer, Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, adequate bone marrow, liver, and renal function, no pre-existing neuropathy greater than grade 1, and measurable disease, from 55 hospitals and 51 private practices in Germany. After 24 weeks of induction therapy with either fluorouracil plus leucovorin plus oxaliplatin or capecitabine plus oxaliplatin, both with bevacizumab, patients without disease progression were randomly assigned centrally by fax (1:1:1) to standard maintenance treatment with a fluoropyrimidine plus bevacizumab, bevacizumab alone, or no treatment. Both patients and investigators were aware of treatment assignment. Stratification criteria were response status, termination of oxaliplatin, previous adjuvant treatment with oxaliplatin, and ECOG performance status. At first progression, re-induction with all drugs of the induction treatment was a planned part of the protocol. Time to failure of strategy was the primary endpoint, defined as time from randomisation to second progression after maintenance (and if applicable re-induction), death, or initiation of further treatment including a new drug. Time to failure of strategy was equivalent to time to first progression for patients who did not receive re-induction (for any reason). The boundary for assessment of non-inferiority was upper limit of the one-sided 98·8% CI 1·43. Analyses were done by intention to treat. The study has completed recruitment, but follow-up of participants is ongoing. The trial is registered with ClinicalTrials.gov, number NCT00973609. FINDINGS: Between Sept 17, 2009, and Feb 21, 2013, 837 patients were enrolled and 472 randomised; 158 were randomly assigned to receive fluoropyrimidine plus bevacizumab, 156 to receive bevacizumab monotherapy, and 158 to receive no treatment. Median follow-up from randomisation is 17·0 months (IQR 9·5-25·4). Median time to failure of strategy was 6·9 months (95% CI 6·1-8·5) for the fluoropyrimidine plus bevacizumab group, 6·1 months (5·3-7·4) for the bevacizumab alone group, and 6·4 months (4·8-7·6) for the no treatment group. Bevacizumab alone was non-inferior to standard fluoropyrimidine plus bevacizumab (hazard ratio [HR] 1·08 [95% CI 0·85-1·37]; p=0·53; upper limit of the one-sided 99·8% CI 1·42), whereas no treatment was not (HR 1·26 [0·99-1·60]; p=0·056; upper limit of the one-sided 99·8% CI 1·65). The protocol-defined re-induction after first progression was rarely done (30 [19%] patients in the fluoropyrimidine plus bevacizumab group, 67 [43%] in the bevacizumab monotherapy group, and 73 [46%] in the no treatment group. The most common grade 3 adverse event was sensory neuropathy (21 [13%] of 158 patients in the fluoropyrimidine plus bevacizumab group, 22 [14%] of 156 patients in the bevacizumab alone group, and 12 [8%] of 158 patients in the no treatment group). INTERPRETATION: Although non-inferiority for bevacizumab alone was demonstrated for the primary endpoint, maintenance treatment with a fluoropyrimidine plus bevacizumab may be the preferable option for patients following an induction treatment with a fluoropyrimidine, oxaliplatin, and bevacizumab, as it allows the planned discontinuation of the initial combination without compromising time with controlled disease. Only a few patients were exposed to re-induction treatment, thus deeming the primary endpoint time to failure of strategy non-informative and clinically irrelevant. Progression-free survival and overall survival should be considered primary endpoints in future trials exploring maintenance strategies.

TFAP2E-DKK4 and chemoresistance in colorectal cancer.

BACKGROUND: Chemotherapy for advanced colorectal cancer leads to improved survival; however, predictors of response to systemic treatment are not available. Genomic and epigenetic alterations of the gene encoding transcription factor AP-2 epsilon (TFAP2E) are common in human cancers. The gene encoding dickkopf homolog 4 protein (DKK4) is a potential downstream target of TFAP2E and has been implicated in chemotherapy resistance. We aimed to further evaluate the role of TFAP2E and DKK4 as predictors of the response of colorectal cancer to chemotherapy. METHODS: We analyzed the expression, methylation, and function of TFAP2E in colorectal-cancer cell lines in vitro and in patients with colorectal cancer. We examined an initial cohort of 74 patients, followed by four cohorts of patients (total, 220) undergoing chemotherapy or chemoradiation. RESULTS: TFAP2E was hypermethylated in 38 of 74 patients (51%) in the initial cohort. Hypermethylation was associated with decreased expression of TFAP2E in primary and metastatic colorectal-cancer specimens and cell lines. Colorectal-cancer cell lines overexpressing DKK4 showed increased chemoresistance to fluorouracil but not irinotecan or oxaliplatin. In the four other patient cohorts, TFAP2E hypermethylation was significantly associated with nonresponse to chemotherapy (P<0.001). Conversely, the probability of response among patients with hypomethylation was approximately six times that in the entire population (overall estimated risk ratio, 5.74; 95% confidence interval, 3.36 to 9.79). Epigenetic alterations of TFAP2E were independent of mutations in key regulatory cancer genes, microsatellite instability, and other genes that affect fluorouracil metabolism. CONCLUSIONS: TFAP2E hypermethylation is associated with clinical nonresponsiveness to chemotherapy in colorectal cancer. Functional assays confirm that TFAP2E-dependent resistance is mediated through DKK4. In patients who have colorectal cancer with TFAP2E hypermethylation, targeting of DKK4 may be an option to overcome TFAP2E-mediated drug resistance. (Funded by Deutsche Forschungsgemeinschaft and others.).

Label-free imaging of drug distribution and metabolism in colon cancer cells by Raman microscopy.

Targeted cancer therapies block cancer growth and spread using small molecules. Many molecular targets for an epidermal growth factor receptor (EGFR) selectively compete with the adenosine triphosphate-binding site of its tyrosine kinase domain. Detection of molecular targeted agents and their metabolites in cells/tissues by label-free imaging is attractive because dyes or fluorescent labels may be toxic or invasive. Here, label-free Raman microscopy is applied to show the spatial distribution of the molecular targeted drug erlotinib within the cell. The Raman images show that the drug is clustered at the EGFR protein at the membrane and induces receptor internalization. The changes within the Raman spectrum of erlotinib measured in cells as compared to the free-erlotinib spectrum indicate that erlotinib is metabolized within cells to its demethylated derivative. This study provides detailed insights into the drug targeting mechanism at the atomic level in cells. It demonstrates that Raman microscopy will open avenues as a non-invasive and label-free technique to investigate pharmacokinetics at the highest possible resolution in living cells.

Docetaxel, oxaliplatin and capecitabine (TEX regimen) in patients with metastatic gastric or gastro-esophageal cancer: results of a multicenter phase I/II study.

UNLABELLED: Three drug taxane-based regimens have shown activity in patients with metastatic or locally advanced gastric or gastro-esophageal cancer (GC/GEC). Limited tolerability of these regimens warrants treatment modification, particularly in regard of the proven equivalence of oxaliplatin and cisplatin as well as capecitabine and 5FU. Thus, a regimen with docetaxel (T), oxaliplatin (E) and capecitabine (X) was established and evaluated. METHODS: Patients with metastatic or locally advanced GC/GEC, adequate organ function, ECOG PS 0-2 were enrolled. TEX regimen was administered as defined by the phase I trial with T 35 mg/m(2) and E 70 mg/m(2) on days (d) 1, 8 and X 800 mg/m(2) bid on d 1-14 every 22 days. Primary endpoint was progression free survival (PFS) rate after 6 months. RESULTS: Altogether 70 patients (15 phase I; 55 phase II) were eligible for analysis. Results of the phase II part were as follows: most common grade toxicities diarrhea (30%), nausea/vomiting and infections, PFS rate after 6 months 56.3%, response rate 43%, median PFS 6.9 and overall survival 13 months, respectively. CONCLUSION: The TEX regimen show similar efficacy compared to other infusional 5FU-based taxane and platinum containing triplets, but the reduced tolerability, in particular grade 3 diarrhea, limits the feasibility.