Microscopic Tumor Foci Research Articles

Unusual presentation of incidental atypical carcinoid tumor masquerading as carcinoid tumorlets arising from diffuse neuroendocrine cell hyperplasia (DIPNECH): A case report

Introduction: Carcinoid tumorlets are usually incidental findings in lung excisions. These neuroendocrine proliferations should be less than 5 mm, and resemble typical carcinoid (TC) lacking necrosis and elevated mitotic activity. We report a case of atypical carcinoid (AC) presenting as multiple tumors all measuring less than 5 mm, mimicking carcinoid tumorlets. Case Report: Our patient underwent a right upper lobectomy for multifocal invasive lepidic adenocarcinoma. Multiple nodules of neuroendocrine cells less than 5 mm in greatest dimension were noted within the lobectomy. Unlike carcinoid tumorlets, these nodules showed >2 mitotic figures per square millimeter and punctate necrosis. The ACs masqueraded as multiple microscopic tumor foci (greater5 mm) resembling “carcinoid tumorlets” in adjacent background lung tissue next to the adenocarcinoma. However, increased mitoses and punctate necrosis were diagnostic of AC. A background of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) was noted, appeared to be a precursor lesion to AC, and demonstrated the DIPNECH’s preneoplastic potential to evolve directly into an AC. Conclusion: The rare possibility of AC in “tumorlet”-appearing multiple micronodules should be considered in presence of elevated mitotic activity and necrosis in background of DIPNECH.

Targeted SERS Imaging and Intraoperative Real-Time Elimination of Microscopic Tumors for Improved Breast-Conserving Surgery.

Breast-conserving surgery is the favorable option for breast cancer patients owing to its advantages of less aggressiveness and better cosmetic outcomes over mastectomy. However, it often suffers from postsurgical lethal recurrence due to the incomplete removal of microscopic tumors. Here, a surface-enhanced Raman scattering (SERS) surgical strategy is reported for precise delineation of tumor margins and intraoperative real-time elimination of microscopic tumor foci, which is capable of complete surgical removal of breast tumors and significantly improve the outcomes of breast-conserving surgery without local tumor recurrence. The technique is chiefly based on the human epidermal growth factor receptor 2 (HER2)-targeting SERS probes with integrated multifunctionalities of ultrahigh sensitive detection, significant HER2 expression suppression, cell proliferation inhibition, and superior photothermal ablation. In a HER2+ breast tumor mouse model, the remarkable capability of the SERS surgical strategy for complete removal of HER2+ breast tumors through SERS-guided surgical resection and intraoperative real-time photothermal elimination is demonstrated. The results show complete eradiation of HER2+ breast tumors without local recurrence, consequently delivering a 100% tumor-free survival. Expectedly, this SERS surgical strategy holds great promise for clinical treatment of HER2+ breast cancer with improved patients' survival.

Abstract 3205: MicroRNA-peptide polyelectrolyte complex nanoparticle-hydrogel composite attenuates mesothelioma growth

Abstract Diffuse pleural mesothelioma (DPM) is a biologically unusual, aggressive asbestos-associated cancer affecting the entire pleura surface. DPM defies current standard multimodal therapies due to intrinsic chemoresistance and inability to achieve negative-margin resection of complex surface anatomy. Hence, current non-specific drug regimens ultimately fail because the biology of this tumor is poorly understood and even if surgically resected, tumor inevitably recurs from residual microscopic tumor foci. These various clinical challenges led us to develop a therapeutic platform delivering microRNA (miRNA), a novel anti-cancer agent therapeutic regimen, with the goal of eradicating residual microscopic tumor foci thereby improving the efficacy of multimodal therapy. We engineered a peptide-based biodegradable hydrogel that can be injected or sprayed directly to coat anatomic surfaces (surface-fill hydrogel; SFH), functioning as a therapeutic depot. Properties of SFH allow us to specify critical composition parameters such as biopersistence time, therapeutic payload, cell-specific targeting etc. In the first step of SFH formulation, miRNA complexed with different amphiphilic cationic peptides varying in length (19-26 amino acids) and amines (9-17), to form stable nanoparticles. Flash nanocomplexation (FNC) were used to produce highly scalable and kinetically controlled assembly of miRNA-peptide polyelectrolyte complex (PEC) nanoparticles (NPs), which utilizes a confined impinging jet (CIJ) mixer to achieve turbulent micromixing of the NPs components, yielding highly uniform and stable NPs. Next, NPs were encapsulated into another peptide hydrogel, formed via self-assembly of amphiphilic cationic peptide HLT2, thus forming a surface-fill hydrogel NPs composite. The SFH-NPs composite was not toxic to DPM cells and demonstrated efficient release of miRNA-peptide NPs from the SFH matrix in-vitro. The uptake of FAM-labeled miRNA-peptide NPs was confirmed by flowcytometry. Biodistribution analysis of NPs in mice bearing luciferase-positive DPM xenografts treated locally with Cy3-miRNA-SFH composite showed that Cy3-miRNA was concentrated in tumor cells but not in other organs. Furthermore, miR-215 exhibiting potent anti-tumor activity in DPM was used to study the therapeutic efficacy of SFH miRNA-nanoparticle composites. Subcutaneous DPM xenografts treated locally with miR-215 SFH composite shrank tumor significantly. Thus, delivery of specific miRNA-peptide PEC nanoparticles via SFH therapeutic platform in preclinical models of DPM displayed potent anti-cancer effects. Together, this new generation microRNA-peptide polyelectrolyte complex nanoparticles-SFH composite is a very promising delivery platform that could be extended for a diverse array of locoregional therapies. Citation Format: Anand Singh, Anderson Caleb, Joel P. Schneider, Chuong D. Hoang. MicroRNA-peptide polyelectrolyte complex nanoparticle-hydrogel composite attenuates mesothelioma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3205.

Lacrimal Gland Intravascular Micrometastasis From a Human Papillomavirus-Driven Anorectal Squamous Cell Carcinoma With a Review of Metastatic Disease to the Lacrimal Gland

To document a unique case of anorectal squamous cell carcinoma that was metastatic to the microvasculature of the lacrimal gland in a patient with human immunodeficiency virus and to review previously reported cases of metastases to the lacrimal gland. Both a retrospective chart review and comprehensive literature review were performed. The unusual histopathologic pattern of the current case was illustrated with immunohistochemical studies (CD31, D2-40, pancytokeratin, p16, and p63) and in situ hybridization studies for high-risk human papillomavirus types 16 and 18. The authors describe the first case of metastatic anorectal squamous cell carcinoma to the lacrimal gland. Only 24 cases of metastatic disease to the lacrimal gland have been reported, the majority from breast carcinomas. The metastasis did not form a macroscopic lesions, instead was composed of microscopic intravascular and intraparenchymal tumor deposits, a subtle phenomena. Immunohistochemistry confirmed the presence of the intravascular neoplastic cells. p16 served as a surrogate marker for human papillomavirus-associated squamous cell carcinoma and was confirmed with in situ hybridization for human papillomavirus 16 and 18. This testing, combined with the clinical history, defined the diagnosis and confirmed human papillomavirus as the tumor driver. Metastases to the lacrimal gland remain rare, but clinicians and pathologists alike must be attuned to the possibility of subtle microscopic foci of tumor as a pattern of metastasis in scenarios without a discrete mass-forming lesion, as this may portend a poor prognosis.

Abstract 6583: Systems scale characterization of malignant pleural mesothelioma to discover novel therapies

Abstract We have built a platform integrating systems genetics and functional genomics for the discovery of therapies to eradicate residual microscopic tumor foci after surgical resection of the deadly cancer malignant pleural mesothelioma (MPM). Using our SYstems Genetics Network AnaLysis (SYGNAL) network inference pipeline we constructed a malignant pleural mesothelioma gene regulatory network to discover disease causing TFs and miRNAs regulatory interactions. We then overlaid the MPM gene regulatory network with significant hits from pooled CRISPR-Cas9 knock-out out growth functional genomics screens in low passage number MPM patient-derived cell lines. We then queried this integrated network to identify patient survival associated TFs and miRNAs that when knocked-down (siRNA) or over-expressed (miRNA mimic), respectively, are likely to have anti-proliferative effects in low passage number patient-derived cell lines. The perturbation of a majority of these TFs and miRNAs led to significantly lower proliferation in the patient-derived cell lines. Further, the expression of the regulator or its target genes should function as a biomarker(s) for whether therapy will be effective for a particular patient's tumor. We are currently working with our collaborator at the NCI to develop these siRNA and miRNAs into their existing miRNA mimic hydrogel delivery system and test them in orthotopic xenografts using the low passage number patient derived cell lines. Citation Format: Sierra F. Wilferd, Chuong D. Hoang, Christopher L. Plaisier. Systems scale characterization of malignant pleural mesothelioma to discover novel therapies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6583.

Abstract 1110: A novel peptide based microRNA nanoparticle hydrogel composite attenuates mesothelioma growth

Abstract Malignant pleural mesothelioma (MPM) is an aggressive cancer resistant to multimodal therapies. Current therapeutic drug regimens ultimately fail due to a poor understanding of the pathogenic mechanisms. After surgical resection, MPM inevitably recurs from residual microscopic tumor foci. These clinical challenges led us to design a locoregional therapeutic platform delivering microRNA (miRNA), a novel anti-cancer agent, intrapleurally, with the goal of eradicating residual microscopic tumor foci thereby improving the efficacy of multimodal therapy. We developed a peptide-based biodegradable hydrogel that can be injected or sprayed directly to coat anatomic surfaces, functioning as a therapeutic depot. Properties of the hydrogel were fine-tuned for biopersistence time, therapeutic payload, cell-specific targeting etc. In the first step of formulation, miRNA complexed with an amphiphilic cationic peptide forms stable nanoparticles. Next, miRNA-nanoparticles were encapsulated into another peptide hydrogel, formed via self-assembly of amphiphilic cationic peptide, thus forming a nanoparticle-hydrogel composite. The hydrogel could be delivered by syringe or spray to surfaces, mold to contours, adhere and maintain integrity in-vitro as well as in-vivo. The composite material was nontoxic to MPM cells and demonstrated the efficient release of miRNA-peptide nanoparticles from the large hydrogel matrix in-vitro. Tracking of Cy3-labeled scrambled miRNA-nanoparticles by confocal microscopy showed nanoparticle uptake by cells was accomplished via a clathrin-dependent endocytosis mechanism. Furthermore, we determined that late endosome escape permitted the release of intact miRNA into the cytoplasm of MPM cells. Pathologic analysis showed macrophages degrading the hydrogel material in-vivo. Cy3-miRNA-hydrogel composite injected subcutaneously in mice showed sustained miRNA release over three weeks. In mice bearing luciferase-positive MPM xenografts (pleural or peritoneal) treated locally with Cy3-miRNA-hydrogel composite, the Cy3-miRNA was concentrated in tumor cells but not in other organs. miRNAs targeting specific molecular vulnerabilities of MPM were used to study the therapeutic efficacy of miRNA-nanoparticle-hydrogel composites. Subcutaneous xenografts treated locally with MPM-specific miRNA-hydrogel composite shrank significantly. Similarly, pleural and peritoneal orthotopic xenografts treated with specific miRNA-hydrogel composite regressed over time. Kaplan-Meier analysis showed that miRNA-hydrogel treatment improved overall survival of tumor-bearing mice. Thus, delivery of specific miRNA via a locoregional therapeutic platform in preclinical models of MPM resulted in beneficial anti-cancer effects. This peptide-based material is promising for translational studies of nucleic acid-based locoregional therapy against MPM. Citation Format: Anand Singh, Poulami Majumder, Joel Schneider, Chuong Dinh Hoang. A novel peptide based microRNA nanoparticle hydrogel composite attenuates mesothelioma growth [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1110.

Minimally invasive tumor bed implant (MITBI) and peri-operative high-dose-rate brachytherapy (PHDRBT) for accelerated minimal breast irradiation (AMBI) or anticipated boost (A-PHDRBT-boost) in breast-conserving surgery for ductal carcinoma in situ.

PurposeTo evaluate our institutional experience of minimally invasive tumor bed implantation (MITBI) during breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) to deliver peri-operative high-dose-rate brachytherapy (PHDRBT) as accelerated minimal breast irradiation (AMBI) or anticipated boost (A-PHDRBT-boost).Material and methodsPatients older than 40, with clinical and radiological unifocal DCIS < 3 cm were considered potential candidates for accelerated partial breast irradiation (APBI) and were implanted during BCS using MITBI-technique. Patients who in final pathology reports showed free margins and no other microscopic tumor foci, received AMBI with PHDRBT (3.4 Gy BID in 5 days). Patients with adverse features received A-PHDRBT-boost with post-operative external beam radiotherapy (EBRT).ResultsForty-one patients were implanted, and 36 were treated and analyzed. According to final pathology, 24 (67%) patients were suitable for AMBI and 12 (33%) were qualified for A-PHDRBT-boost. Reoperation rate for those with clear margins was 16.6% (6/36); this rate increased to 33% (4/12) for G3 histology, and 66% (4/6) were rescued using AMBI. Early complications were documented in 5 patients (14%). With a median follow-up of 97 (range, 42-138) months, 5-year rates of local, elsewhere, locoregional, and distant control were all 97.2%. 5-year ipsilateral breast tumor recurrence rates (IBTR) were 5.6% (2/36), 8.3% (2/24) for AMBI, and 0% (0/12) for A-PHDRBT-boost patients. Both instances of IBTR were confirmed G3 tumors in pre-operative biopsies; no IBTR was documented in G1-2 tumors. Cosmetic outcomes were excellent/good in 96% of AMBI vs. 67% in A-PHDRBT-boost (p = 0.034).ConclusionsThe MITBI-PHDRBT program allows selection of patients with excellent prognoses (G1-2 DCIS with negative margins and no multifocality), for whom AMBI could be a good alternative with low recurrence rate, decrease of unnecessary radiation, treatment logistics improvement, and over-treatment reduction. Patients whose pre-operative biopsy showed G3 tumor, presents with inferior local control and more risk of reoperation due to positive margins.

Signal to Noise Ratio as a Cross-Platform Metric for Intraoperative Fluorescence Imaging.

Real-time molecular imaging to guide curative cancer surgeries is critical to ensure removal of all tumor cells; however, visualization of microscopic tumor foci remains challenging. Wide variation in both imager instrumentation and molecular labeling agents demands a common metric conveying the ability of a system to identify tumor cells. Microscopic disease, comprised of a small number of tumor cells, has a signal on par with the background, making the use of signal (or tumor) to background ratio inapplicable in this critical regime. Therefore, a metric that incorporates the ability to subtract out background, evaluating the signal itself relative to the sources of uncertainty, or noise is required. Here we introduce the signal to noise ratio (SNR) to characterize the ultimate sensitivity of an imaging system and optimize factors such as pixel size. Variation in the background (noise) is due to electronic sources, optical sources, and spatial sources (heterogeneity in tumor marker expression, fluorophore binding, and diffusion). Here, we investigate the impact of these noise sources and ways to limit its effect on SNR. We use empirical tumor and noise measurements to procedurally generate tumor images and run a Monte Carlo simulation of microscopic disease imaging to optimize parameters such as pixel size.

Endonasal endoscopic resection of olfactory neuroblastoma: an 11-year experience.

Olfactory neuroblastoma (ONB) is a rare malignant neoplasm of the sinonasal cavity. Surgery has been and remains a mainstay of treatment for patients with this tumor. Open craniofacial resections have been the treatment of choice for many decades. More recently, experience has been growing with endoscopic approaches in the management of patients with ONB. The object of this study is to report the authors' experience over the past 11 years with ONB patients treated with purely endonasal endoscopic techniques. The authors performed a retrospective chart review of 20 consecutive patients with ONB who underwent a completely endonasal endoscopic approach for an oncological tumor resection at their institution between January 2006 and January 2017. Patient demographics, tumor stage, pathological grade, frozen section analysis, permanent margin assessment, perioperative complications, postoperative therapy, length of follow-up, and outcomes at last follow-up were collected and analyzed. Eighteen patients presented with newly diagnosed disease, with a modified Kadish stage of A in 2 cases, B in 3, C in 11, and D in 2. Two patients presented with recurrent tumors. An average of 25.3 specimens per patient were examined by frozen section analysis. Although analysis of intraoperative frozen section margins was negative in all but 1 case, microscopic foci of tumor were found in 7 cases (35%) on permanent histopathological analysis. Perioperative complications occurred in 7 patients (35%) including 1 patient who developed a cerebrospinal fluid leak; there were no episodes of meningitis. All but 1 patient received postoperative radiotherapy, and 5 patients received postoperative chemotherapy. With a mean follow-up of over 5 years, 19 patients were alive and 1 patient died from an unrelated cause. There were 2 cases of tumor recurrence. The 5-year overall, disease-specific, and recurrence-free survival rates were 92.9%, 100%, and 92.9%, respectively. The current results provide additional evidence for the continued use of endoscopic procedures in the management of this malignancy.

Absorbed dose evaluation at different organs after 131I oral contamination of two Wistar rat models

Iodine-131 (131I) is one of the most frequently used radionuclides for diagnosis and therapy of thyroid diseases. It is administered orally in the treatment of cancer to eliminate the residual postoperative microscopic tumor foci, and the residual normal thyroid tissue for early detection of recurrence [1]. The comparative behavior of 131I concentration into two animalmodels with total and partial thyroid has been investigated in our previous work [2]. The accumulated activities have been measured in fourteen organs. In this study, the mean absorbed doses resulting from 131I accumulated in all organs have been evaluated using RODES software [3, 4]. With this software, mean absorbed doses were calculatedfor selected organs (thyroid, lungs, heart, liver, kidneys, stomach, spleen, large and small intestine, testes, urinary bladder wall) by combining the specific absorbed fractions (SAF) of energy with radiation emission spectra and biokinetic data determined from our previous experimental study [2]. Calculations were based on the 131I photon and electron emissions reported by [5] and SAFs previously calculated by Monte Carlo simulation in the voxel phantom of an adult male rate [3, 4]. The obtained results show high absorbed dosesdeliveredto stomach and lungs for both models compared to other organs. The dose received by the testes and salivary glands is found to be higher in the case of the rat model without thyroid. Conversely, the spleen and bladder wall received lower doses in this latter model compared to those received by the rat model with thyroid. One can also note that the difference in mean absorbed dose received by liver, lungs, heart, and walls of the stomach is not significant between the two rat models.

Tumor cell seeding in the biopsy tract and its clinical significance in osteosarcomas.

The reasons behind the removal of the biopsy tract in osteosarcomas are not well known, and studies about tumor seeding in the biopsy tract have generated conflicting results. This study is designed to evaluate the presence and possible clinical significance of tumor cell seeding in the biopsy tract of osteosarcomas. We prospectively evaluated 55 cases of osteosarcomas for tumor cell seeding and other clinical and pathologic prognostic parameters. Eleven cases (20%) involved microscopic tumor foci in the biopsy tract. The higher local recurrence rates (P = 0.005) and worse recurrence-free survivals ( P = 0.009) were observed in patients with tumor cell foci in the biopsy tract. Mitotic rate, tumor cell pleomorphism, and matrix production in main tumor foci were higher in cases with tumor seeding ( P = 0.047, P = 0.012, and P = 0.005, respectively) CONCLUSIONS: Tumor seeding in the biopsy tract is a fact in osteosarcomas. The higher local recurrence rates are more likely to occur in cases with tumor seeding.

Analysis of Peripheral Nerve Schwannoma Pseudocapsule

Using proper surgical technique, schwannomas can be resected safely, with a low recurrence rate and high likelihood of improvement in symptomatology. There are multiple peritumoral tissue layers, and finding the correct plane is critical to safe tumor enucleation. The contents of the pseudocapsule tissue surrounding a schwannoma are not well described, and the consequences of resecting or leaving pseudocapsules are unknown. An institutional database was searched for any pathology reports that contained both of the words "schwannoma" and "capsule." Charts and histopathologic specimens were reviewed to determine the contents of various tissue layers and determine if there was any correlation between pseudocapsular contents and clinical outcomes. A pseudocapsule was separately sent for pathology in 36 patients during schwannoma resection. Ten pseudocapsule specimens contained microscopic foci of tumor. In a separate 6 patients, there was evidence of nerve fascicles. There were no correlations between the tumor or nerve in the pseudocapsule and postoperative neurologic deficits. After an average follow-up time of 3.1 years, no patients developed a recurrence either clinically or on follow-up imaging (imaging available in 52.7%). Histopathologically, the pseudocapsule was made of dense hypocellular collagen and occasionally contained arteries, veins, and nerve fascicles. The pseudocapsule surrounding a schwannoma occasionally contained nerve tissue and blood vessels. While a microscopic focus of tumor was often found in this tissue layer, recurrence is exceedingly rare and did not occur in this case series. The risk of undue pseudocapsule dissection likely outweighs any negligible benefit from microscopic cytoreduction.

Prospective Evaluation of Intrahepatic Microscopic Occult Tumor Foci in Patients with Numerous Colorectal Liver Metastases

Background: Patients with numerous colorectal liver metastases (CLM) have high risk of early recurrence after liver resection (LR). The presence of intrahepatic occult microscopic metastases missed by imaging has been hypothesized, but it has never been assessed by pathology analyses. Methods: All patients with > 10 CLM who underwent LR between September 2015 and September 2016 were considered. A large sample of liver without evidence of disease (“healthy liver”) was taken from the resected specimen and sent to the pathologist. One mm-thick sections were analyzed. Any metastasis, undetected by preoperative and intraoperative imaging, but identified by the pathologist was classified as occult microscopic metastasis. Results: Ten patients were prospectively enrolled (median number of CLM n = 15). In a per-lesion analysis, the sensitivity of computed tomography and magnetic resonance imaging was 91 and 98% respectively. The pathology examination confirmed all the CLM. All patients had an adequate sample of “healthy liver” (median number of examined blocks per sample n = 14 [5–33]). No occult microscopic metastases were detected. After a median follow-up of 15 months, 5 patients were disease-free. Recurrence was hepatic and bilobar in all patients. Conclusions: Clinically relevant occult microscopic disease in patients with numerous CLM is excluded. These results support the indication to resection in such patients and exclude the need for de principe major hepatectomy to increase the completeness of surgery.

Hepatic micrometastases are associated with poor prognosis in patients with liver metastases from neuroendocrine tumors of the digestive tract

Pathologic examination of hepatic metastasectomies from patients with metastatic small intestinal or pancreatic neuroendocrine tumor frequently reveals micrometastases undetectable by radiologic or macroscopic gross examination. This finding raises the possibility that undetectable micrometastases remain in these patients after metastasectomy. Here we examined liver resections for micrometastases and assessed their impact on prognosis. Hepatic metastasectomies from 65 patients with neuroendocrine tumor of the small intestine (N = 43) or pancreas (N = 22) were reviewed for the presence of micrometastases, which were defined as microscopic tumor foci ≤1 mm in greatest dimension. Medical records were also reviewed for patient demographics, clinical history, and follow-up data. Micrometastasis was identified in 36 (55%) of 65 hepatic resection specimens. More hepatic micrometastases were seen in small intestinal cases than in pancreatic cases (29/43, 67%, versus 7/22, 32%; P < .01). They were typically present within portal tracts, sometimes with extension into the periportal region or sinusoidal spaces away from the portal tracts. Patients without hepatic micrometastases had fewer macrometastases or more R0 hepatic resections than those with micrometastases. The presence of hepatic micrometastases was associated with poor overall survival both before (hazard ratio [HR] 3.43; 95% CI 1.14-10.30; P = .03) and after accounting for confounding variables in stratified Cox regression (HR 4.82; 95% CI 1.0621.79; P = .04). In conclusion, hepatic micrometastases are common in patients with metastatic small intestinal or pancreatic neuroendocrine tumor and are independently associated with poor prognosis. These data suggest that surgical resection of hepatic metastases is likely not curative in these patients.

Highlights of This Issue

Disease recurrence after curative resection for hepatocellular carcinoma (HCC) patients remains the major cause for dismal outcome. Results from this large-sample prospective randomized controlled trial showed that adjuvant transarterial chemoembolization (TACE), along with adriamycin and lipiodol, can significantly reduce tumor recurrence, improve recurrence-free survival and overall survival for HBV-related HCC patients with an intermediate or high risk of HCC recurrence after curative liver resection. The data also suggests that adjuvant TACE decreases HCC recurrence after curative liver resection by eradicating pre-existing microscopic tumor foci that traditional imaging modalities fail to detect in the perioperative stage and is well tolerated.In clinical practice, no validated biomarkers are currently available to predict the efficacy of pemetrexed plus platinum doublet chemotherapy for nonsquamous NSCLC patients. This study investigated the metabolic characteristics of 354 prechemotherapeutic serum samples and found tight associations between small metabolites and the responses of patients to this cytotoxic drug combination. An effective discriminant model was developed by employing a seven-metabolite panel, which can predict the efficacy of the chemotherapeutic regimens, prior to treatment, with a sensitivity of 90.8% and specificity of 79.5%. This serum-based biomarker study can be easily applied in clinical practice and personalize treatment decisions.Successful implementation of HPV screening requires triage to distinguish transforming from benign HPV infections. Previous studies have shown associations of HPV DNA methylation with cervical precancer for some HPV types. In this study, Clarke and colleagues observed strong associations of increased methylation with precancer in all 12 carcinogenic HPV types, suggesting that DNA methylation is a general phenomenon in the transition from HPV infection to precancer. HPV methylation showed good risk stratification and better performance than current triage methods. A multi-type methylation assay may solve the current problem of how to manage HPV-positive women, in high- and low-resource settings.The Cancer Genome Atlas data resources represent an opportunity to explore commonalities across 32 different cancer types involving multiple molecular levels. Chen and colleagues applied an alternative molecular classification approach to over 10,000 tumor samples to define ten major pan-cancer “classes” that transcended tissue or histology distinctions. Coordinate pathways and processes were revealed across these pan-cancer classes, and the influence of the tumor microenvironment was evident within distinct subsets of human tumors. One molecular class manifesting a differential expression profile of neuroendocrine tumors could have therapeutic implications for an appreciable subset of human cancers.

Tumor dormancy and frailty models: A novel approach.

Frailty models are here proposed in the tumor dormancy framework, in order to account for possible unobservable dependence mechanisms in cancer studies where a non-negligible proportion of cancer patients relapses years or decades after surgical removal of the primary tumor. Relapses do not seem to follow a memory-less process, since their timing distribution leads to multimodal hazards. From a biomedical perspective, this behavior may be explained by tumor dormancy, i.e., for some patients microscopic tumor foci may remain asymptomatic for a prolonged time interval and, when they escape from dormancy, micrometastatic growth results in a clinical disease appearance. The activation of the growth phase at different metastatic states would explain the occurrence of metastatic recurrences and mortality at different times (multimodal hazard). We propose a new frailty model which includes in the risk function a random source of heterogeneity (frailty variable) affecting the components of the hazard function. Thus, the individual hazard rate results as the product of a random frailty variable and the sum of basic hazard rates. In tumor dormancy, the basic hazard rates correspond to micrometastatic developments starting from different initial states. The frailty variable represents the heterogeneity among patients with respect to relapse, which might be related to unknown mechanisms that regulate tumor dormancy. We use our model to estimate the overall survival in a large breast cancer dataset, showing how this improves the understanding of the underlying biological process.

High Precision Imaging of Microscopic Spread of Glioblastoma with a Targeted Ultrasensitive SERRS Molecular Imaging Probe

The dismal prognosis of patients with malignant brain tumors such as glioblastoma multiforme (GBM) is attributed mostly to their diffuse growth pattern and early microscopic tumor spread to distant regions of the brain. Because the microscopic tumor foci cannot be visualized with current imaging modalities, it remains impossible to direct treatments optimally. Here we explored the ability of integrin-targeted surface-enhanced resonance Raman spectroscopy (SERRS) nanoparticles to depict the true tumor extent in a GBM mouse model that closely mimics the pathology in humans. The recently developed SERRS-nanoparticles have a sensitivity of detection in the femtomolar range. An RGD-peptide-conjugated version for integrin-targeting (RGD-SERRS) was compared directly to its non-targeted RAD-SERRS control in the same mice via Raman multiplexing. Pre-blocking with RGD peptide before injection of RGD-SERRS nanoparticles was used to verify the specificity of integrin-targeting. In contrast to the current belief that the enhanced permeability and retention (EPR) effect results in a baseline uptake of nanoparticles regardless of their surface chemistry, integrin-targeting was shown to be highly specific, with markedly lower accumulation after pre-blocking. While the non-targeted SERRS particles enabled delineation of the main tumor, the RGD-SERRS nanoparticles afforded a major improvement in visualization of the true extent and the diffuse margins of the main tumor. This included the detection of unexpected tumor areas distant to the main tumor, tracks of migrating cells of 2-3 cells in diameter, and even isolated distant tumor cell clusters of less than 5 cells. This Raman spectroscopy-based nanoparticle-imaging technology holds promise to allow high precision visualization of the true extent of malignant brain tumors.

Personalized—Not Omitted—Radiation Oncology for Breast Cancer

TO THE EDITOR: The article by Bellon 1 reports that radiation therapy (RT) for breast cancer (BC) could be omitted for patients who are unlikely to benefit from locoregional therapy. In fact, an absolute improvement of local control less than 10% correlated with a BC mortality benefit of only 0.1%. Moreover, in the editorial, RT was described as being inconvenient because of toxicity. We appreciated that it was highlighted that no data supported the omission of RT after breast-conserving surgery (BCS) and that this possibility remains only speculative. In fact, the recent meta-analysis conducted by the Early Breast Cancer Trialists’ Collaborative Group 2 showed that, during the next 15 years, approximately one death from BC would be avoided for every four local recurrences avoided. It is well recognized that killing of locoregional microscopic tumor foci reduces the potential risk of local recurrences and distant metastasis. 2 Regarding the possibility of omitting RT in selected patients with BC without definitive data, several questions could emerge. First, can we omit a local treatment if it does not increase overall survival? In other cancer diseases, such as rectal cancer, the standard conservative treatment approach, including RT, reduces the risk of locoregional recurrences without increasing overall survival. To our knowledge, the omission of RT has never been discussed. Undoubtedly, the reduction of local recurrences improve quality of life for patients with BC. In European Organisation for Research and Treatment of Cancer (EORTC) trial 10801, BCS with RT was associated with a better body image compared with a mastectomy approach. 3 Second, considering the increased risk of local failure when RT is omitted, shall we consider more intensive follow-up? Two randomized trials did not show any effect of intensive diagnostic follow-up on 5- and 10-year mortality for patients with primary BC treated with BCS and RT. 4,5 Therefore, these data are no longer reliable if RT is not performed, and, probably, intensive follow-up should be proposed to patients to prevent local recurrence, increasing health care system costs.

Hedgehog-driven myogenic tumors recapitulate skeletal muscle cellular heterogeneity

Hedgehog (Hh) pathway activation in R26-SmoM2;CAGGS-CreER mice, which carry a tamoxifen-inducible activated Smoothened allele (SmoM2), results in numerous microscopic tumor foci in mouse skeletal muscle. These tumors exhibit a highly differentiated myogenic phenotype and resemble human fetal rhabdomyomas. This study sought to apply previously established strategies to isolate lineally distinct populations of normal mouse myofiber-associated cells in order to examine cellular heterogeneity in SmoM2 tumors. We demonstrate that established SmoM2 tumors are composed of cells expressing myogenic, adipocytic and hematopoietic lineage markers and differentiation capacity. SmoM2 tumors thus recapitulate the phenotypic and functional hetereogeneity observed in normal mouse skeletal muscle. SmoM2 tumors also contain an expanded population of PAX7+ and MyoD+ satellite-like cells with extremely low clonogenic activity. Selective activation of Hh signaling in freshly isolated muscle satellite cells enhanced terminal myogenic differentiation without stimulating proliferation. Our findings support the conclusion that SmoM2 tumors represent an aberrant skeletal muscle state and demonstrate that, similar to normal muscle, myogenic tumors contain functionally distinct cell subsets, including cells lacking myogenic differentiation potential.

Abstract 2056: Identification of microscopic ovarian tumor foci utilizing a novel imaging device in a murine ovarian cancer model, an opportunity to improve optimal cytoreduction

Abstract Survival of ovarian cancer patients is directly related to the amount of residual disease present after debulking surgery. In 80% of the cases, extensive microscopic cancer remains even after the patient is deemed optimally debulked. Hence, detection of sub-mm cancer clusters during tumor excision is a critical unmet need. Recent studies have shown that reducing the dimensions of residual cancer to less than 1 mm significantly improves clinical outcomes. In the present study we evaluate the performance of a fluorescent, molecular imaging agent, LUM015 (Lumicell, Wellesley, MA), which is activated by cathepsin enzymes in the tumor, and a wide-field-of-view imaging device (Lumicell) to detect sub-mm residual cancer clusters in an mouse model for ovarian cancer. In this study, we generated orthotopic ovarian cancer mouse models(n=10) with well characterized serous ovarian cancer cell lines, CP70 and SKOV3. Once the tumor disseminated, the imaging agent LUM015 (3.52 mg/kg) was injected via the tail vein, and after 6 hours, the mice were euthanized. Tumor debulking was performed throughout the abdominal cavity. After debulking, the whole abdominal wall was dissected in 4 quadrants, organs were harvested and all were imaged with the LUM device. Features exhibiting high fluorescence were marked and dissected, prepared into slides, and stained with hematoxylin and eosin for pathologic correlation with LUM015 fluorescence imaging. In 36 tissues from orthotopic ovarian cancer mouse models, LUM015 imaging system could detect the tumor presence with 100% of sensitivity and 60% of specificity. We demonstrated that the imaging system can detect sub-mm cancer clusters that could not be identified with visual inspection. With a cathepsin activated fluorescence imaging molecule (LUM015) and a wide-field-of-view imaging device, we detected microscopic residual ovarian cancer tumors in orthotopic xenograft models after debulking grossly with high sensitivity. Translation of this imaging technology into the clinical setting may help to detect microscopic residual tumor features during the debulking operation in ovarian cancer. Citation Format: Youngjeong Na, Tim Kwok, Christopher Awtrey, David B. Strasfeld, Jorge M. Ferrer, David Lee, Michael J. Birrer. Identification of microscopic ovarian tumor foci utilizing a novel imaging device in a murine ovarian cancer model, an opportunity to improve optimal cytoreduction. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2056. doi:10.1158/1538-7445.AM2014-2056