A foundation model for clinical-grade computational pathology and rare cancers detection.

The analysis of histopathology images with artificial intelligence aims to enable clinical decision support systems and precision medicine. The success of such applications depends on the ability to model the diverse patterns observed in pathology images. To this end, we present Virchow, the largest foundation model for computational pathology to date. In addition to the evaluation of biomarker prediction and cell identification, we demonstrate that a large foundation model enables pan-cancer detection, achieving 0.95 specimen-level area under the (receiver operating characteristic) curve across nine common and seven rare cancers. Furthermore, we show that with less training data, the pan-cancer detector built on Virchow can achieve similar performance to tissue-specific clinical-grade models in production and outperform them on some rare variants of cancer. Virchow's performance gains highlight the value of a foundation model and open possibilities for many high-impact applications with limited amounts of labeled training data.

Artificial Intelligence Helps Pathologists Increase Diagnostic Accuracy and Efficiency in the Detection of Breast Cancer Lymph Node Metastases.

The detection of lymph node metastases is essential for breast cancer staging, although it is a tedious and time-consuming task where the sensitivity of pathologists is suboptimal. Artificial intelligence (AI) can help pathologists detect lymph node metastases, which could help alleviate workload issues. We studied how pathologists' performance varied when aided by AI. An AI algorithm was trained using more than 32 000 breast sentinel lymph node whole slide images (WSIs) matched with their corresponding pathology reports from more than 8000 patients. The algorithm highlighted areas suspicious of harboring metastasis. Three pathologists were asked to review a dataset comprising 167 breast sentinel lymph node WSIs, of which 69 harbored cancer metastases of different sizes, enriched for challenging cases. Ninety-eight slides were benign. The pathologists read the dataset twice, both digitally, with and without AI assistance, randomized for slide and reading orders to reduce bias, separated by a 3-week washout period. Their slide-level diagnosis was recorded, and they were timed during their reads. The average reading time per slide was 129 seconds during the unassisted phase versus 58 seconds during the AI-assisted phase, resulting in an overall efficiency gain of 55% ( P <0.001). These efficiency gains are applied to both benign and malignant WSIs. Two of the 3 reading pathologists experienced significant sensitivity improvements, from 74.5% to 93.5% ( P ≤0.006). This study highlights that AI can help pathologists shorten their reading times by more than half and also improve their metastasis detection rate.

Randomized Phase 2 Clinical Trial of Olaratumab in Combination with Gemcitabine and Docetaxel in Advanced Soft Tissue Sarcomas.

Gemcitabine plus docetaxel is an effective treatment regimen for advanced soft tissue sarcomas (STSs). However, the prognosis for patients remains poor, and thus there is an urgent medical need for novel and effective therapies to improve long-term outcomes. The aim of the ANNOUNCE 2 trial was to explore the addition of olaratumab (O) to gemcitabine (G) and docetaxel (D) for advanced STS. Adults with unresectable locally advanced/metastatic STS, ≤2 prior lines of systemic therapy, and ECOG PS 0-1 were eligible. In Phase 2, patients were randomized 1:1 from two cohorts (O-naïve and O-pretreated) to 21-day cycles of olaratumab (20 mg/kg Cycle 1 and 15 mg/kg other cycles, Days 1 and 8), gemcitabine (900 mg/m2, Days 1 and 8), and docetaxel (75 mg/m2, Day 8). The primary objective was overall survival (OS) in the O-naïve population (α level = 0.20). Secondary endpoints included OS (O-pretreated), other efficacy parameters, patient-reported outcomes, safety, pharmacokinetics, and immunogenicity. A total of 167 and 89 patients were enrolled in the O-naïve and O-pretreated cohorts, respectively. Baseline patient characteristics were well balanced. No statistically significant difference in OS was observed between the investigational vs. control arm for either cohort (O-naïve cohort: HR = 0.95 (95% CI: 0.64-1.40), p = 0.78, median OS, 16.8 vs. 18.0 months; O-pretreated cohort: HR = 0.67 (95% CI: 0.39-1.16), p = 0.15, median OS 19.8 vs. 17.3 months). Safety was manageable across treatment arms. There was no statistically significant difference in the primary endpoint of OS between the two arms in the O-naïve population, and therefore based on hierarchical evaluation no other outcomes in this study can be considered statistically significant. No new safety signals were observed.

Analytical Accuracy of RET Fusion Detection by Break-Apart Fluorescence In Situ Hybridization.

CONTEXT.­: RET gene fusions are oncogenic drivers in nonsmall cell lung cancer and nonmedullary thyroid cancer. Selpercatinib (RETEVMO), a targeted inhibitor of RET, was approved by the US Food and Drug Administration for the treatment of RET fusion-positive nonsmall cell lung cancer and nonmedullary thyroid cancer emphasizing the need for rapid and accurate diagnosis of RET fusions. Fluorescence in situ hybridization (FISH) has been used to detect gene rearrangements, but its performance detecting RET rearrangements is understudied. OBJECTIVE.­: To validate and describe the performance of Abbott Molecular RET break-apart FISH probes for detecting RET rearrangements. DESIGN.­: A training set with RET fusion-positive (13) and RET fusion-negative nonsmall cell lung cancer and nonmedullary thyroid cancer samples (12) was used to establish criteria for FISH scoring. The scoring criteria was then applied to a larger validation set of samples (96). RESULTS.­: A cutoff of 19% or more positive nuclei by FISH was established in the training set and determined by the mean ±3 SD. The validation set was tested using Abbott Molecular RET break-apart FISH compared with sequencing. With this cutoff, a sensitivity of 86% (12 of 14) and specificity of 99% (81 of 82) was achieved. Bootstrapping showed sensitivity could be optimized by using a greater than 13% cutoff with indeterminate samples of 13% to 18% abnormal nuclei requiring confirmation by an orthogonal method. Using this 3-tier scoring system sensitivity increased to 100% (14 of 14) and specificity was 96% (79 of 82). CONCLUSIONS.­: Abbott Molecular break-apart FISH probes can be used to detect RET fusions. Laboratories can optimize cutoffs and/or testing algorithms to maximize sensitivity and specificity to ensure appropriate patients receive effective, timely therapy.

A phase 1b study of the Notch inhibitor crenigacestat (LY3039478) in combination with other anticancer target agents (taladegib, LY3023414, or abemaciclib) in patients with advanced or metastatic solid tumors.

Notch signaling plays an important role in development and tissue homeostasis. Deregulation of Notch signaling has been implicated in multiple malignancies. Crenigacestat (LY3039478), a potent Notch inhibitor, decreases Notch signaling and its downstream biologic effects. I6F-MC-JJCD was a multicenter, nonrandomized, open-label, Phase 1b study with 5 separate, parallel dose-escalations in patients with advanced or metastatic cancer from a variety of solid tumors, followed by a dose-confirmation phase in prespecified tumor types. This manuscript reports on 3 of 5 groups. The primary objective was to determine the recommended Phase 2 dose of crenigacestat in combination with other anticancer agents (taladegib, LY3023414 [dual inhibitor of phosphoinositide 3-kinase; mechanistic target of rapamycin], or abemaciclib). Secondary objectives included evaluation of safety, tolerability, efficacy, and pharmacokinetics. Patients (N = 63) received treatment between November 2016 and July 2019. Dose-limiting toxicities occurred in 12 patients, mostly gastrointestinal (diarrhea, nausea, vomiting). The maximum-tolerated dose of crenigacestat was 25 mg in Part B (LY3023414), 50 mg in Part C (abemaciclib), and not established in Part A (taladegib) due to toxicities. Patients had at least 1 adverse event (AE) and 75.0-82.6% were ≥ Grade 3 all-causality AEs. No patient had complete or partial response. Disease control rates were 18.8% (Part B) and 26.1% (Part C). The study was terminated before dose confirmation cohorts were triggered. This study demonstrated that crenigacestat combined with different anticancer agents (taladegib, LY3023414, or abemaciclib) was poorly tolerated, leading to lowered dosing and disappointing clinical activity in patients with advanced or metastatic solid tumors. NCT02784795 and date of registration: May 27, 2016.

Phase 1 study to evaluate Crenigacestat (LY3039478) in combination with dexamethasone in patients with T-cell acute lymphoblastic leukemia and lymphoma.

BACKGROUND: Deregulated Notch signaling is implicated in T-cell acute lymphoblastic leukemia (T-ALL)/T-cell lymphoblastic lymphoma (T-LBL). Crenigacestat (LY3039478) prevents cleavage of Notch proteins and may benefit patients with relapsed/refractory T-ALL/T-LBL. METHODS: JJCB was a multicenter, nonrandomized, open-label, dose-escalation, phase 1 study in adult patients with relapsed/refractory T-ALL/T-LBL. Eligible patients received Crenigacestat orally 3 times per week plus dexamethasone at 24 mg twice daily on days 1 to 5 every other week in a 28-day cycle. The starting level of Crenigacestat was 50 mg, and dose escalation was performed with a modified 3+3 scheme for the estimation of dose-limiting toxicity (DLT) at the recommended dose level. RESULTS: In total, 36 patients with T-ALL (n = 31 [86.1%]) or T-LBL (n = 5 [13.9%]) were treated with Crenigacestat and dexamethasone. Six patients (16.7%) experienced DLTs: 2 of 12 (16.7%) in the 75-mg cohort (grade 4 gastrointestinal hemorrhage and grade 3 nausea, vomiting, and diarrhea), 1 of 15 (6.7%) in the 100-mg cohort (grade 3 diarrhea), and 3 of 3 (100%) in the 125-mg cohort (grade 3 diarrhea, nausea, and vomiting). The maximum tolerated dosewas 75 mg plus 24 mg of dexamethasone daily on days 1 to 5. Twenty-eight patients (77.8%) experienced 1 or more treatment-emergent adverse events related to the study treatment. The best overall response was a confirmed response, with 1 patient (2.8%) having a duration of response of 10.51 months. Six patients (16.7%) achieved stable disease, and 12 patients (33.3%) experienced progressive disease. The remaining 17 patients (47.2%) were not evaluable. The median event-free survival was 1.18 months (95% confidence interval, 0.76-2.14 months) among all groups. A pharmacodynamic analysis showed decreased plasma amyloid ß levels. CONCLUSIONS: Crenigacestat demonstrated limited clinical activity at the recommended dose in adult patients with relapsed/refractory T-ALL/T-LBL.

Circulating Tumor Cells and Biomarker Modulation with Olaratumab Monotherapy Followed by Olaratumab plus Doxorubicin: Phase Ib Study in Patients with Soft-Tissue Sarcoma.

This phase Ib study enumerated whole blood circulating tumor cells (CTC) and evaluated biomarkers in patients with potentially resectable soft-tissue sarcoma (STS) treated with olaratumab monotherapy (20 mg/kg) for one cycle followed by up to six cycles of olaratumab (20 mg/kg, cycles 1-2; 15 mg/kg, cycles 3-7) plus doxorubicin (75 mg/m2 on day 1). CTCs, platelet-derived growth factor receptors (PDGFR), and PDGF ligand expression in tumor tissue pre- and post-olaratumab monotherapy were evaluated. Antitumor activity, safety, pharmacokinetics, and PET/biomarker association with clinical outcome were assessed. Of 51 treated patients, 35, 43, and 37 were evaluable for CTC enumeration, PDGFRs, and PDGF ligand expression, respectively. An increase in CTCs at cycle 1 day 8 was observed, followed by a significant reduction by cycle 3 day 1 or 30-day follow-up. Decrease in CTC counts after olaratumab monotherapy was higher in patients with disease control than without disease control (57.9% vs. 31.2%). Baseline IHC expression was positive in most patients for PDGFRα [n = 31 (72.1%)] and PDGFRß [n = 36 (83.7%)]. Similar rates were observed post-olaratumab monotherapy [PDGFRα, n = 30 (69.8%); PDGFRß, n = 33 (76.7%)]. Eleven patients (29.7%) showed a 30% reduction by RT-PCR in PDGFRα at cycle 2. PDGFR expression and PET response showed no correlation with clinical outcome. Safety and pharmacokinetic profiles were consistent with previous reports. This study, the first to use a validated method for CTC detection, confirms that CTC enumeration in STS is feasible. However, no correlation was observed between PDGFRα expression and clinical outcome.

Phase 1 study of 2 high dose intensity schedules of the pan-Notch inhibitor crenigacestat (LY3039478) in combination with prednisone in patients with advanced or metastatic cancer.

Background Crenigacestat is a potent Notch inhibitor that decreases Notch signaling and its downstream biological effects. Here, we report the results from Part F of study 16F-MC-JJCA designed to evaluate the safety, pharmacokinetics (PK), and antitumor activity of crenigacestat with prednisone in advanced or metastatic cancer. The combination was planned to mitigate gastrointestinal toxicities. Methods Eligible patients (Study Part F) received crenigacestat loading dose (75 mg, escalating to 150 mg) administered thrice weekly (TIW) (F1) or twice weekly (BIW) (F2) for 2 weeks during Cycle 1, followed by 50 mg TIW from week 3 onwards. Prednisone was co-administered for 2 weeks in Cycle 1. Results Twenty-eight patients were enrolled; 11 in F1 (median age, 63 years), 17 in F2 (median age, 50 years). Dose-limiting toxicities were Grade 3 increased serum amylase and Grade 2 fatigue in F1, and Grade 4 hypophosphatemia and Grade 3 rash maculo-papular in F2. The maximum tolerated dose was 75 mg in F1 and 100 mg in F2. Best overall response was stable disease (F1, 6 [54.5%] patients; F2, 11 [64.7%] patients). Pharmacokinetic was dose proportional. Prednisone did not modify PK of crenigacestat, and both F1 and F2 achieved pharmacodynamics effects on evaluable tumor tissue samples. Conclusions This study demonstrated the potential use of prednisone to reduce gastrointestinal (GI) toxicities of a Notch inhibitor without affecting its PK. The safety profile observed was consistent with Notch pathway inhibitors, and the maximum tolerated dose was 75 mg TIW and 100 mg BIW in F1 and F2, respectively. ClinicalTrials.gov: NCT01695005.

A Randomized Phase III Study of Abemaciclib Versus Erlotinib in Patients with Stage IV Non-small Cell Lung Cancer With a Detectable KRAS Mutation Who Failed Prior Platinum-Based Therapy: JUNIPER.

INTRODUCTION: JUNIPER compared the efficacy and safety of abemaciclib, a selective cyclin-dependent kinase 4 and 6 inhibitor, with erlotinib in patients with non-small cell lung cancer (NSCLC) harboring a Kirsten rat sarcoma (KRAS) mutation. METHODS: JUNIPER was a Phase III, multicenter, randomized, open-label trial of abemaciclib versus erlotinib in patients with stage IV NSCLC and a detectable mutation in codons 12 or 13 of the KRAS oncogene, who progressed after platinum-based chemotherapy and 1 additional therapy (could include immune checkpoint inhibitor therapy). Randomized patients (3:2) received either 200 mg abemaciclib twice daily or 150 mg erlotinib once daily with best supportive care until disease progression or unacceptable toxicity. The primary endpoint was overall survival (OS); secondary endpoints included overall response rate (ORR), progression-free survival (PFS), and safety. RESULTS: Between December 2014 and April 2017, 453 patients were randomly assigned to receive abemaciclib (N = 270) or erlotinib (N = 183). Median OS was 7.4 months (95% confidence interval [CI]: 6.5, 8.8) with abemaciclib and 7.8 months (95% CI: 6.4, 9.5) with erlotinib (hazard ratio [HR] = 0.968 [95% CI: 0.768, 1.219]; p = .77). Median PFS was 3.6 months (95% CI: 2.8, 3.8) with abemaciclib and 1.9 months (95% CI: 1.9, 2.0) with erlotinib (HR = 0.583 [95% CI: 0.470, 0.723]; p <.000001). ORR was 8.9% and 2.7% (p = .010), and the disease control rate was 54.4% and 31.7% (p <.001) with abemaciclib and erlotinib, respectively. Safety results reflected the known safety profiles of abemaciclib and erlotinib. CONCLUSIONS: In this study, the primary endpoint of OS was not met; PFS and ORR were improved with manageable toxicity in the abemaciclib arm. The increases in response rates and PFS support further investigation of abemaciclib in other NSCLC subpopulations or in combination with other agents. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier: NCT02152631.

The Genomic Landscape of Intrinsic and Acquired Resistance to Cyclin-Dependent Kinase 4/6 Inhibitors in Patients with Hormone Receptor-Positive Metastatic Breast Cancer.

Mechanisms driving resistance to cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in hormone receptor-positive (HR+) breast cancer have not been clearly defined. Whole-exome sequencing of 59 tumors with CDK4/6i exposure revealed multiple candidate resistance mechanisms including RB1 loss, activating alterations in AKT1, RAS, AURKA, CCNE2, ERBB2, and FGFR2, and loss of estrogen receptor expression. In vitro experiments confirmed that these alterations conferred CDK4/6i resistance. Cancer cells cultured to resistance with CDK4/6i also acquired RB1, KRAS, AURKA, or CCNE2 alterations, which conferred sensitivity to AURKA, ERK, or CHEK1 inhibition. Three of these activating alterations-in AKT1, RAS, and AURKA-have not, to our knowledge, been previously demonstrated as mechanisms of resistance to CDK4/6i in breast cancer preclinically or in patient samples. Together, these eight mechanisms were present in 66% of resistant tumors profiled and may define therapeutic opportunities in patients. SIGNIFICANCE: We identified eight distinct mechanisms of resistance to CDK4/6i present in 66% of resistant tumors profiled. Most of these have a therapeutic strategy to overcome or prevent resistance in these tumors. Taken together, these findings have critical implications related to the potential utility of precision-based approaches to overcome resistance in many patients with HR+ metastatic breast cancer.This article is highlighted in the In This Issue feature, p. 1079.

Phase 1 study of olaratumab plus doxorubicin in Japanese patients with advanced soft-tissue sarcoma.

Olaratumab, a monoclonal antibody targeting human platelet-derived growth factor receptor α, plus doxorubicin significantly improved overall survival in patients with advanced soft-tissue sarcoma (STS) in a prior phase 1b/2 randomized trial. Subsequent exposure-response analysis suggested that higher olaratumab exposures earlier might improve outcomes in patients at risk of early disease progression. This phase 1 study (3 treatment cohorts; minimum 6 patients each) investigated the safety, pharmacokinetics and antitumor activity of olaratumab plus doxorubicin in Japanese patients with STS. Patients received olaratumab 15 mg/kg on Days 1 and 8 during each 21-day cycle until disease progression. Patients in Cohort 3 received a 20 mg/kg loading dose of olaratumab in Cycle 1. Doxorubicin was administered for up to 6 cycles. Patients in Cohort 1 received doxorubicin 25 mg/m2 on Days 1, 2 and 3. Patients in Cohorts 2 and 3 received doxorubicin 75 mg/m2 on Day 1. One patient in Cohort 2 experienced a dose-limiting toxicity of Grade 3 febrile neutropenia. Most treatment-emergent adverse events were of mild and moderate severity, and were known doxorubicin toxicities. Olaratumab serum concentrations in Cohort 3 reached a steady-state exceeding the target level in Cycle 1. Partial response was confirmed in 4 patients (2 each in Cohorts 2 and 3). Olaratumab plus doxorubicin had an acceptable safety profile in patients with STS. A loading dose of olaratumab 20 mg/kg was effective for achieving minimum serum concentrations above the target trough level in Cycle 1.

Notch pathway inhibition with LY3039478 in soft tissue sarcoma and gastrointestinal stromal tumours.

BACKGROUND: LY3039478 is an orally bioavailable selective Notch inhibitor. This phase 1a/b trial evaluated the safety, pharmacokinetics and antitumour activity of LY3039478 in patients with soft tissue sarcoma (STS) and gastrointestinal stromal tumour (GIST). METHODS: This multipart, phase 1 trial enrolled patients with refractory advanced/metastatic STS and GIST, measurable disease, Eastern Cooperative Oncology Group ≤1 and baseline tumour tissue. Eligible patients received LY3039478 50mg/75 mg three times per week, for 28-day cycle until disease progression. Safety assessments were based on Common Terminology Criteria for Adverse Events, V4.0. Tumour responses were assessed using Response Evaluation Criteria in Solid Tumours (RECIST 1.1) and Choi criteria. Primary objectives were to confirm the recommended phase 2 dose of LY3039478 and document the antitumour activity. Secondary objectives were safety and toxicity, pharmacokinetics (PK), progression-free survival (PFS) and overall survival (OS). RESULTS: Sixty-nine patients were enrolled and received LY3039478 (27 males, 42 females; median age 58, range 31-78). 16/37 (43%) patients with evaluable samples were positive for Notch 1 immunohistochemistry. Per RECIST 1.1, in leiomyosarcoma (LMS) group (n = 29), ten (36%) had stable disease (SD) and one (4%) had unconfirmed partial response (PR). In GIST group (n = 13), four (31%) had SD. Among other STS subtypes (n = 27), one patient with angiosarcoma had unconfirmed PR, six (21%) had SD. Median PFS was 1.9 months (95% confidence interval:1.6-3.3) for LMS, 1.9 months (0.3-6.1) for GIST and 1.7 months (1.4-2.2) for other STS groups. Median OS was 7.4 months (4.3-non-evaluable [NE]) for LMS, 16.5 months (3.9-16.5) for GIST and 5.6 months (3.4-NE) for other STS groups. Most common adverse events were diarrhoea, nausea, vomiting and decreased appetite. CONCLUSION: LY3039478 suggested a modest clinical activity in patients with STS and GIST and had a manageable safety profile.

Olaratumab Exerts Antitumor Activity in Preclinical Models of Pediatric Bone and Soft Tissue Tumors through Inhibition of Platelet-Derived Growth Factor Receptor α.

Purpose: Platelet-derived growth factor receptor α (PDGFRα) is implicated in several adult and pediatric malignancies, where activated signaling in tumor cells and/or cells within the microenvironment drive tumorigenesis and disease progression. Olaratumab (LY3012207/IMC-3G3) is a human mAb that exclusively binds to PDGFRα and recently received accelerated FDA approval and conditional EMA approval for treatment of advanced adult sarcoma patients in combination with doxorubicin. In this study, we investigated olaratumab in preclinical models of pediatric bone and soft tissue tumors.Experimental Design: PDGFRα expression was evaluated by qPCR and Western blot analysis. Olaratumab was investigated in in vitro cell proliferation and invasion assays using pediatric osteosarcoma and rhabdoid tumor cell lines. In vivo activity of olaratumab was assessed in preclinical mouse models of pediatric osteosarcoma and malignant rhabdoid tumor.Results:In vitro olaratumab treatment of osteosarcoma and rhabdoid tumor cell lines reduced proliferation and inhibited invasion driven by individual platelet-derived growth factors (PDGFs) or serum. Furthermore, olaratumab delayed primary tumor growth in mouse models of pediatric osteosarcoma and malignant rhabdoid tumor, and this activity was enhanced by combination with either doxorubicin or cisplatin.Conclusions: Overall, these data indicate that olaratumab, alone and in combination with standard of care, blocks the growth of some preclinical PDGFRα-expressing pediatric bone and soft tissue tumor models. Clin Cancer Res; 24(4); 847-57. ©2017 AACR.

"Simple Mucinous Cyst" of the Pancreas: A Clinicopathologic Analysis of 39 Examples of a Diagnostically Challenging Entity Distinct From Intraductal Papillary Mucinous Neoplasms and Mucinous Cystic Neoplasms.

Pancreatic cysts >1 cm lined by nonpapillary mucinous epithelium without ovarian-type stroma pose diagnostic challenges. The term "simple mucinous cyst" was recently proposed for this entity. Our goal was to determine the clinicopathologic characteristics of these cysts, as they have not been previously described. Of the 39 patients with pancreatic resections included in this study, the mean age was 65 years and the female-to-male ratio was 4:1. The characteristics of the cysts are as follows: 82% had elevated cyst fluid carcinoembryonic antigen levels, 67% were unilocular, 69% occurred in the body/tail, 92% did not communicate with pancreatic ducts, the mean size was 2.4 cm (range, 1.0 to 5.5 cm), the cyst contents tended to be serous (48%) or viscous (28%), all had a smooth lining (only 1 had focal excrescences) composed of bland columnar mucinous epithelium (low-grade dysplasia) in 92% with focal high-grade dysplasia in 8%, and 65% had degenerative changes (granulation-like tissue, hemorrhage, and myxoid stroma). The cyst lining was CK7+ and 97% had a MUC5AC+ and/or MUC6+ gastric phenotype; overt intestinal features were absent. In total, 55% of cysts tested (fluid and/or resections) harbored KRAS mutations. The term "simple mucinous cyst" is useful to apply to >1 cm mucinous cysts that do not have characteristic features of intraductal papillary mucinous neoplasms or mucinous cystic neoplasms. KRAS mutations can be detected in these typically bland cysts, and in rare instances, focal high-grade dysplasia may be present. Hence, these cysts should be viewed as neoplastic and treated similarly to other mucinous pancreatic cysts.

Variability in Platelet-Derived Growth Factor Receptor Alpha Antibody Specificity May Impact Clinical Utility of Immunohistochemistry Assays.

Aberrant regulation of the receptor tyrosine kinase platelet-derived growth factor alpha (PDGFRα) is implicated in several types of cancer. Inhibition of the PDGFRα pathway may be a beneficial therapy, and detection of PDGFRα in tumor biopsies may lead to insights about which patients respond to therapy. Exploratory or clinical biomarker use of PDGFRα IHC has been frequently reported, often with polyclonal antibody sc-338. An sc-338-based assay was systematically compared with anti-PDGFRα rabbit monoclonal antibody D13C6 using immunoblot profiling and IHC in formalin-fixed and paraffin-embedded human tumor cell lines. Application of sc-338 to blots of whole cell lysates showed multiple bands including some of unknown origin, whereas application of D13C6 resulted in a prominent band at the expected molecular mass of PDGFRα. The IHC assay using D13C6 showed appropriate staining in cell lines, whereas the assay using sc-338 suggested nonspecific detection of proteins. An optimized IHC assay using D13C6 showed a range of staining in the tumor stromal compartment in lung and ovarian carcinomas. These observations suggest that use of clone sc-338 produced unreliable results and should not be used for an IHC research grade assay. In addition, this precludes its use as a potential antibody for a clinical diagnostic tool.

Same difference: A pilot study of cyclin D1, bcl-2, AMACR, and ALDH-1 identifies significant differences in expression between primary colon adenocarcinoma and its metastases.

Tumor heterogeneity implies the possibility of significantly different expression of key pathways between primary and metastatic clones. Colon adenocarcinoma is one of the few tumors where current practice includes resection of primary and isolated organ metastases simultaneously without neoadjuvant therapy. We performed a pilot study on 28 cases of colon adenocarcinoma resected simultaneously with metastases in patients with no history of neoadjuvant therapy. We assayed matched primary and metastatic tumors from each patient with common diagnostic antibodies to Bcl-2, Cyclin D1, AMACR, and ALDH-1 by immunohistochemistry with semi-quantitative interpretation on archived formalin fixed, paraffin embedded samples. We were powered for large, consistent differences between primary and metastatic expression, and found 21 of 28 had a significant difference in expression of at least one of the four proteins, accounting for multiplicity of testing. Cyclin D1 had significantly more cases with differential metastatic:primary expression than would be expected by chance alone (p-value 0.0043), favoring higher expression in the metastatic sample. Bcl-2 and ALDH-1 had trends in this direction (p-value 0.078 each). Proportionately more cases with significant differences were identified when a liver metastasis was tested. We conclude differences in expression between metastatic and primary colon adenocarcinoma within the same patient exist, and may have therapeutic and biomarker testing consequences.

Chemo-predictive assay for targeting cancer stem-like cells in patients affected by brain tumors.

Administration of ineffective anticancer therapy is associated with unnecessary toxicity and development of resistant clones. Cancer stem-like cells (CSLCs) resist chemotherapy, thereby causing relapse of the disease. Thus, development of a test that identifies the most effective chemotherapy management offers great promise for individualized anticancer treatments. We have developed an ex vivo chemotherapy sensitivity assay (ChemoID), which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents. Two patients, a 21-year old male (patient 1) and a 5-month female (patient 2), affected by anaplastic WHO grade-III ependymoma were screened using the ChemoID assay. Patient 1 was found sensitive to the combination of irinotecan and bevacizumab, which resulted in a prolonged disease progression free period of 18 months. Following recurrence, the combination of various chemotherapy drugs was tested again with the ChemoID assay. We found that benzyl isothiocyanate (BITC) greatly increased the chemosensitivity of the ependymoma cells to the combination of irinotecan and bevacizumab. After patient 1 was treated for two months with irinotecan, bevacizumab and supplements of cruciferous vegetable extracts containing BITC, we observed over 50% tumoral regression in comparison with pre-ChemoID scan as evidenced by MRI. Patient 2 was found resistant to all treatments tested and following 6 cycles of vincristine, carboplatin, cyclophosphamide, etoposide, and cisplatin in various combinations, the tumor of this patient rapidly progressed and proton beam therapy was recommended. As expected animal studies conducted with patient derived xenografts treated with ChemoID screened drugs recapitulated the clinical observation. This assay demonstrates that patients with the same histological stage and grade of cancer may vary considerably in their clinical response, suggesting that ChemoID testing which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents could lead to more effective and personalized anticancer treatments in the future.

A novel mutation in the succinate dehydrogenase subunit D gene in siblings with the hereditary paraganglioma-pheochromocytoma syndrome.

Germline mutations in the succinate dehydrogenase complex subunit D gene are now known to be associated with hereditary paraganglioma-pheochromocytoma syndromes. Since the initial succinate dehydrogenase complex subunit D gene mutation was identified about a decade ago, more than 131 unique variants have been reported. We report the case of two siblings presenting with multiple paragangliomas and pheochromocytomas; they were both found to carry a mutation in the succinate dehydrogenase complex subunit D gene involving a substitution of thymine to guanine at nucleotide 236 in exon 3. This particular mutation of the succinate dehydrogenase complex subunit D gene has only been reported in one previous patient in Japan; this is, therefore, the first report of this pathogenic mutation in siblings and the first report of this mutation in North America. With continued screening of more individuals, we will be able to create a robust mutation database that can help us understand disease patterns associated with particular variants and may be a starting point in the development of new therapies for familial paraganglioma syndromes.