A Phase III Study of Pafolacianine Injection (OTL38) for Intraoperative Imaging of Folate Receptor-Positive Ovarian Cancer (Study 006).

PURPOSE: The adjunctive use of intraoperative molecular imaging (IMI) is gaining acceptance as a potential means to improve outcomes for surgical resection of targetable tumors. This confirmatory study examined the use of pafolacianine for real-time detection of folate receptor-positive ovarian cancer. METHODS: This phase III, open-label, 11-center study included subjects with known or suspected ovarian cancer, scheduled to undergo cytoreductive surgery. The objectives were to confirm safety and efficacy of pafolacianine (0.025 mg/kg IV), given ≥ 1 hour before intraoperative near-infrared imaging to detect macroscopic lesions not detected by palpation and normal white light. RESULTS: From March 2018 through April 2020, 150 patients received a single infusion of pafolacianine (safety analysis set); 109 patients with folate receptor-positive ovarian cancer comprised the full analysis set for efficacy. In 33.0% of patients (95% CI, 24.3 to 42.7; P < .001), pafolacianine with near-infrared imaging identified additional cancer on tissue not planned for resection and not detected by white light assessment and palpation, exceeding the prespecified threshold of 10%. Among patients who underwent interval debulking surgery, the rate was 39.7% (95% CI, 27.0 to 53.4; P < .001). The sensitivity to detect ovarian cancer was 83%, and the patient false-positive rate was 24.8%. Investigators reported achieving complete R0 resection in 62.4% (68 of 109) of patients. Drug-related adverse events were reported by 30% of patients (45 of 150) and most commonly included nausea, vomiting, and abdominal pain. No drug-related serious adverse events or deaths were reported. CONCLUSION: This phase III study of pafolacianine met its primary efficacy end point, identifying additional cancers not otherwise identified or planned for resection. Pafolacianine may offer an important real-time adjunct to current surgical approaches for ovarian cancer.

First-in-Human Phase 1 Study of MORAb-202, an Antibody-Drug Conjugate Comprising Farletuzumab Linked to Eribulin Mesylate, in Patients with Folate Receptor-α-Positive Advanced Solid Tumors.

PURPOSE: MORAb-202, an antibody-drug conjugate containing farletuzumab and eribulin with a cathepsin-B cleavable linker, targets folate receptor α (FRα)-expressing tumor cells. The primary objective of this first-in-human study was to evaluate the safety and tolerability of MORAb-202 in patients with solid tumors. PATIENTS AND METHODS: Patients ≥20 years with adequate organ function and FRα-positive solid tumors who failed to respond to standard therapy were eligible. Patients received MORAb-202 intravenously at doses of 0.3 to 1.2 mg/kg once every three weeks. Endpoints included dose-limiting toxicities, safety, tumor responses, pharmacokinetics, and pharmacodynamics. TRIAL REGISTRATION NUMBER: NCT03386942 (ClinicalTrials.gov). RESULTS: Between November 28, 2017 and June 4, 2019, 22 patients (median age, 58.0 years) with advanced solid tumors were enrolled. Treatment-emergent adverse events occurred in 21 (95%) patients, with leukopenia and neutropenia in 10 (45%) patients each. One patient (0.9 mg/kg cohort) experienced two grade 3 dose-limiting toxicities: serum alanine aminotransferase and γ-glutamyl transferase increases. Following review by an independent adjudication committee, grade 1/2 interstitial lung disease thought to be related to MORAb-202 was identified in five (23%) patients. Complete response, partial response, and stable disease were observed in one, nine, and eight patients, respectively. The normalized predose serum FRα tended to be positively correlated with the maximum tumor shrinkage (R 2 = 0.2379; P = 0.0291). CONCLUSIONS: The MTD of MORAb-202 was not reached. MORAb-202 demonstrated promising antitumor activity in FRα-positive solid tumors and was generally well-tolerated at the tested doses. Further investigations are required to establish appropriate dosage and clinical utility of MORAb-202.

Triple Negative Breast Cancer: Expression of Folate Receptor Alpha in Indian population.

Folate Receptor Alpha (FRA) is a membrane protein expressed on the apical surface of epithelial cells. Its expression in increased in certain tumors, where it can serve as a target for therapy. Triple Negative Breast Carcinoma (TNBC) are a heterogeneous group of tumors, with limited therapy options and poor prognosis. We aimed to study the expression of FRA in TNBC. Tissue microarrays were prepared from archived paraffin blocks of 300 TNBC resection specimens. Staining for FRA immunohistochemistry was carried out using the clone 26B3.F2. Clinical and pathologic details of the patients were obtained from the electronic medical records. Chi square test was performed for correlation of clinicopathological features with FRA expression. Kaplan Meir and Cox Regression analysis were carried out to study the Disease Free Survival (DFS) and Overall Survival (OS). FRA showed positivity in 43% (129/300) of TNBCs in our study. In univariate analysis, TNBC expressing FRA had a significantly better OS compared to FRA negative tumors (p - 0.035). Also, FRA positive tumors showed a trend towards longer DFS, though this was not statistically significant. In multivariate analysis however, FRA expression did not emerge as a significant factor. To conclude, TNBCs in our study showed FRA expression and though this did not emerge as an important prognostic factor, it can represent a therapeutic target for future clinical trials.

A phase II, multicenter, open-label trial of OTL38 injection for the intra-operative imaging of folate receptor-alpha positive ovarian cancer.

PURPOSE: OTL38 is a folate-indole-cyanine green-like conjugate to folate receptor alpha (FRa). The objectives of this prospective trial were to assess the safety and efficacy (sensitivity and positive predictive value (PPV)) of OTL38 for intraoperative imaging during epithelial ovarian cancer surgery. METHODS: Patients with suspected ovarian cancer planned for cytoreductive surgery were eligible to receive OTL38. Near-infrared (NIR) imaging was used to visualize target lesions that were evaluated by two blinded pathologists. A modified intent to treat (mITT) population of lesions from all patients who received OTL38-NIR imaging, underwent surgery, and had at least one FRa + target lesion was used to determine sensitivity and PPV. Two generalized linear models, with and without random effects, were employed to estimate sensitivity and PPV. RESULTS: Forty-four patients were evaluated for safety, and 225 lesions from 29 patients (the mITT population) were evaluated for efficacy. When assuming no correlation of interlesional results within a patient, sensitivity was estimated at 85.93% (95% lower boundary CI = 81.19) and PPV at 88.14% (95% lower boundary CI = 83.59). When controlling for actual correlation of detection among multiple lesions within a single patient (a random effect), sensitivity was estimated at 97.97% (95% lower boundary CI = 87.75) and PPV at 94.93% (95% lower boundary CI = 86.13). A total of 48.3% [14/29, (95% CI 0.29-0.67)] of patients had at least one additional lesion detected by OTL38 alone. Eight patients had mild drug-related adverse events including infusion reaction, nausea, vomiting, and abdominal pain. CONCLUSIONS: OTL38-NIR was safe and efficacious in this phase II study regardless of folate expression levels and merits phase III evaluation.

Detecting Functional and Accessible Folate Receptor Expression in Cancer and Polycystic Kidneys.

Folate-based small molecule drug conjugates (SMDCs) are currently under development and have shown promising preclinical and clinical results against various cancers and polycystic kidney disease. Two requisites for response to a folate-based SMDC are (i) folate receptor alpha (FRα) protein is expressed in the diseased tissues, and (ii) FRα in those tissues is accessible and functionally competent to bind systemically administered SMDCs. Here we report on the development of a small molecule reporter conjugate (SMRC), called EC2220, which is composed of a folate ligand for FRα binding, a multilysine containing linker that can cross-link to FRα in the presence of formaldehyde fixation, and a small hapten (fluorescein) used for immunohistochemical detection. Data show that EC2220 produces a far greater IHC signal in FRα-positive tissues over that produced with EC17, a folate-fluorescein SMRC that is released from the formaldehyde-denatured FRα protein. Furthermore, the extent of the EC2220 IHC signal was proportional to the level of FRα expression. This EC2220-based assay was qualified both in vitro and in vivo using normal tissue, cancer tissue, and polycystic kidneys. Overall, EC2220 is a sensitive and effective reagent for evaluating functional and accessible receptor expression in vitro and in vivo.

Folate transporter expression in placenta from pregnancies complicated with birth defects.

BACKGROUND: Folate plays a fundamental role for fetal development, participating in cell division, embryogenesis, and fetal growth. The fetus depends on maternal supply of folate across the placenta. The objective of this study was to compare the expression of Folate Receptor-α (FR-α), Reduced Folate Carrier (RFC), and Proton Coupled Folate Transporter (PCFT) in placentas from pregnancies complicated with birth defects (BD) and controls. METHODS: Case-control study, including placentas of BD-complicated pregnancies (n = 25) and a control group (n = 25). We determined the placental expression of FR-α, RFC, and PCFT by immunohistochemistry. Optical density was measured to obtain a relative quantification of the expression. RESULTS: The expression of PCFT was greater in placentas from pregnancies complicated with BD than in those from the control group (p < .01). The expression of FR-α and RFC was not different between groups. CONCLUSION: The expression of PCFT in placentas from BD-complicated pregnancies is increased, possibly as an adaptive response to increase the folate flux at the maternal-fetal interface.

Overexpression of folate receptor alpha is an independent prognostic factor for outcomes of pancreatic cancer patients.

Pancreatic cancer has a poor prognosis; hence, novel prognostic markers and effective therapeutic targets should be identified. We aimed to evaluate folate receptor alpha (FR-α) expression in pancreatic cancer and examine its association with clinicopathological features. We utilized tissue samples from 100 primary pancreatic cancer patients who underwent surgery. FR-α was expressed in 37 of 100 cases (37%). The FR-α-positive group (median, 18.8 months) had a significantly poorer prognosis than the FR-α-negative group [median 21.3 months; HR 1.89 (1.12-3.12); P = 0.017]. These groups were not significantly different regarding progression-free survival (P = 0.196). Furthermore, other serum tumor markers including CA19-9 (mean, 186 vs. 822 U/ml; P = 0.001), Dupan-2 (286 vs. 1133 U/ml; P = 0.000), and Span-1 (69.7 vs. 171.9 U/ml; P = 0.006) were significantly downregulated in the FR-α-positive group. CA19-9 was another prognostic factor, in addition to FR-α, and patient prognosis showed clear stratification curves with the expression of these two molecules. Along with CA19-9, FR-α expression was an independent prognostic factor for the overall survival. FR-α and CA19-9 helped predict patient prognosis based on stratification curves.

Tumor Targeting with Novel Pyridyl 6-Substituted Pyrrolo[2,3- d]Pyrimidine Antifolates via Cellular Uptake by Folate Receptor α and the Proton-Coupled Folate Transporter and Inhibition of De Novo Purine Nucleotide Biosynthesis.

Tumor-targeted specificities of 6-substituted pyrrolo[2,3- d]pyrimidine analogues of 1, where the phenyl side-chain is replaced by 3',6' (5, 8), 2',5' (6, 9), and 2',6' (7, 10) pyridyls, were analyzed. Proliferation inhibition of isogenic Chinese hamster ovary (CHO) cells expressing folate receptors (FRs) α and ß were in rank order, 6 > 9 > 5 > 7 > 8, with 10 showing no activity, and 6 > 9 > 5 > 8, with 10 and 7 being inactive, respectively. Antiproliferative effects toward FRα- and FRß-expressing cells were reflected in competitive binding with [3H]folic acid. Only compound 6 was active against proton-coupled folate receptor (PCFT)-expressing CHO cells (∼4-fold more potent than 1) and inhibited [3H]methotrexate uptake by PCFT. In KB and IGROV1 tumor cells, 6 showed <1 nM IC50, ∼2-3-fold more potent than 1. Compound 6 inhibited glycinamide ribonucleotide formyltransferase in de novo purine biosynthesis and showed potent in vivo efficacy toward subcutaneous IGROV1 tumor xenografts in SCID mice.

Utilization of targeted near-infrared molecular imaging to improve pulmonary metastasectomy of osteosarcomas.

Pulmonary metastasectomy for osteosarcoma provides a select group of patients an opportunity for long-term survival and possible cure. Unfortunately, a complete metastasectomy is challenging due an inability to accurately identify lesions that lay below the threshold of preoperative imaging or intraoperative visual and tactile inspection. Growing evidence suggests that osteosarcomas express a number of unique molecular markers, including the folate receptor alpha. In this case report, we describe the application of a folate receptor-targeted, near-infrared optical contrast agent (OTL38) to improve osteosarcoma localization during minimally invasive pulmonary resection. In addition to localizing preoperatively identified lesions, this technology helped identify additional disease that was undetected on preoperative imaging or with traditional intraoperative techniques. This report marks the first successful utilization of a molecular imaging probe useful for osteosarcomas. This technology may provide a unique approach to improve pulmonary metastasectomy of osteosarcomas.

Safety and Activity of Mirvetuximab Soravtansine (IMGN853), a Folate Receptor Alpha-Targeting Antibody-Drug Conjugate, in Platinum-Resistant Ovarian, Fallopian Tube, or Primary Peritoneal Cancer: A Phase I Expansion Study.

Purpose This phase I expansion cohort study evaluated the safety and clinical activity of mirvetuximab soravtansine (IMGN853), an antibody-drug conjugate consisting of a humanized anti-folate receptor alpha (FRα) monoclonal antibody linked to the tubulin-disrupting maytansinoid DM4, in a population of patients with FRα-positive and platinum-resistant ovarian cancer. Patients and Methods Patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer received IMGN853 at 6.0 mg/kg (adjusted ideal body weight) once every 3 weeks. Eligibility included a minimum requirement of FRα positivity by immunohistochemistry (≥ 25% of tumor cells with at least 2+ staining intensity). Adverse events, tumor response (via Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1), and progression-free survival (PFS) were determined. Results Forty-six patients were enrolled. Adverse events were generally mild (≤ grade 2), with diarrhea (44%), blurred vision (41%), nausea (37%), and fatigue (30%) being the most commonly observed treatment-related toxicities. Grade 3 fatigue and hypotension were reported in two patients each (4%). For all evaluable patients, the confirmed objective response rate was 26%, including one complete and 11 partial responses, and the median PFS was 4.8 months. The median duration of response was 19.1 weeks. Notably, in the subset of patients who had received three or fewer prior lines of therapy (n = 23), an objective response rate of 39%, PFS of 6.7 months, and duration of response of 19.6 weeks were observed. Conclusion IMGN853 exhibited a manageable safety profile and was active in platinum-resistant ovarian cancer, with the strongest signals of efficacy observed in less heavily pretreated individuals. On the basis of these findings, the dose, schedule, and target population were identified for a phase III trial of IMGN853 monotherapy in patients with platinum-resistant disease.

Effective adoptive immunotherapy of triple-negative breast cancer by folate receptor-alpha redirected CAR T cells is influenced by surface antigen expression level.

BACKGROUND: The poor prognosis and the limited efficacy of targeted therapy in patients with triple-negative breast cancer (TNBC) have raised the need for alternative therapies. Recent studies have demonstrated that folate receptor-alpha (FRα) may represent an ideal tumor-associated marker for immunotherapy for TNBC. METHODS: The aim of the present study was to apply a chimeric antigen receptor (CAR) approach for the targeting of FRα expressed on TNBC cells and evaluate the antitumor activity of CAR-engineered T cells in vitro and in vivo. RESULTS: We found that human T cells expressing a FRα-specific CAR were potent and specific killers of TNBC cells that express moderate levels of FRα in vitro and significantly inhibited tumor outgrowth following infusion into immunodeficient mice bearing an MDA-MB-231 tumor xenograft. However, the antitumor activity of the FRα CAR T cells was modest when compared to the same CAR T cells applied in an ovarian tumor xenograft model where FRα expression is more abundant. Notably, FRα CAR T cells induced superior tumor regression in vivo against MDA-MB-231 that was engineered for overexpression of FRα. CONCLUSIONS: Taken together, our results show that FRα CAR T cells can mediate antitumor activity against established TNBC tumor, particularly when FRα is expressed at higher levels. These results have significant implications for the pre-selection of patients with high antigen expression levels when utilizing CAR-based adoptive T cell therapies of cancer in future clinical trials.

A TiS2 nanosheet enhanced fluorescence polarization biosensor for ultra-sensitive detection of biomolecules.

Development of new strategies for the sensitive and selective detection of ultra-low concentrations of specific cancer markers is of great importance for assessing cancer therapeutics due to its crucial role in early clinical diagnoses and biomedical applications. In this work, we have developed two types of fluorescence polarization (FP) amplification assay strategies for the detection of biomolecules by using TiS2 as a FP enhancer and Zn(2+)-dependent self-hydrolyzing deoxyribozymes as catalysts to realize enzyme-catalyzed target-recycling signal amplification. One approach is based on the terminal protection of small-molecule-linked DNA, in which biomolecular binding to small molecules in DNA-small-molecule chimeras can protect the conjugated DNA from degradation by exonuclease I (Exo I); the other approach is based on the terminal protection of biomolecular bound aptamer DNA, in which biomolecules directly bound to the single strand aptamer DNA can protect the ssDNA from degradation by Exo I. We select folate receptor (FR) and thrombin (Tb) as model analytes to verify the current concept. It is shown that under optimized conditions, our strategies exhibit high sensitivity and selectivity for the quantification of FR and Tb with low detection limits (0.003 ng mL(-1) and 0.01 pM, respectively). Additionally, this strategy is a simple "mix and detect" approach, and does not require any separation steps. This biosensor is also utilized in the analysis of real biological samples, the results agree well with those obtained by the enzyme-linked immunosorbent assay (ELISA).

Intraoperative imaging of folate receptor alpha positive ovarian and breast cancer using the tumor specific agent EC17.

INTRODUCTION: Intraoperative fluorescence imaging of the folate-receptor alpha (FRα) could support completeness of resection in cancer surgery. Feasibility of EC17, a FRα-targeting agent that fluoresces at 500nm, was demonstrated in a limited series of ovarian cancer patients. Our objective was to evaluate EC17 in a larger group of ovarian cancer patients. In addition, we assessed the feasibility of EC17 in patients with breast cancer. METHODS: Two-to-three hours before surgery 0.1mg/kg EC17 was intravenously administered to 12 patients undergoing surgery for ovarian cancer and to 3 patients undergoing surgery for biopsy-proven FRα-positive breast cancer. The number of lesions/positive margins detected with fluorescence and concordance between fluorescence and tumor- and FRα-status was assessed in addition to safety and pharmacokinetics. RESULTS: Fluorescence imaging in ovarian cancer patients allowed detection of 57 lesions of which 44 (77%) appeared malignant on histopathology. Seven out of these 44 (16%) were not detected with inspection/palpation. Histopathology demonstrated concordance between fluorescence and FRα- and tumor status. Fluorescence imaging in breast cancer patients, allowed detection of tumor-specific fluorescence signal. At the 500nm wavelength, autofluorescence of normal breast tissue was present to such extent that it interfered with tumor identification. CONCLUSIONS: FRα is a favorable target for fluorescence-guided surgery as EC17 produced a clear fluorescent signal in ovarian and breast cancer tissue. This resulted in resection of ovarian cancer lesions that were otherwise not detected. Notwithstanding, autofluorescence caused false-positive lesions in ovarian cancer and difficulty in discriminating breast cancer-specific fluorescence from background signal. Optimization of the 500nm fluorophore, will minimize autofluorescence and further improve intraoperative tumor detection.

Folate receptor α expression and significance in endometrioid endometrium carcinoma and endometrial hyperplasia.

Endometrioid-type endometrial carcinoma (EEC) developing on the ground of endometrial hyperplasia (EH) is amongst the most commonly observed type of cancer in the world. Folate receptor α (FRα) is a vitamin molecule that has a role in cell proliferation. The fact that FRα, which is known to be needed extremely by the cells of malignancies that proliferate rapidly, is present in limited amounts in normal tissues while it is overexpressed in malignant cells of the same tissues makes folate a candidate for target molecular therapy. In our study, FRα expression in 214 cases, with 95 diagnosed within EEC and 119 with EH, was studied immunohistochemically. FRα expression in EEC was found significantly high compared to EH and normal endometrium (P<0.01). Similarly, FRα expression in EH cases with complex atypia were significantly high compared to other hyperplasia subgroups (P<0.01). The findings of our results make us think that FRα overexpression may play a role in the EEC carcinogenesis and carcinoma progression from EH. Furthermore, we suggest that it can be helpful in the treatment of EEC and/or transition from hyperplasia stage to EEC as a molecular therapy targeting receptors labeled with antibody-based props containing FRα. Finally, we suggest that FRα may be used, based on the expression intensity, as a supplemental option to determine the patients that shall be directed to radical therapy amongst patients with complex atypical EH.

Biologically-targeted detection of primary and micro-metastatic ovarian cancer.

Ovarian cancer is the leading cause of morbidity/mortality from gynecologic malignancy. Early detection of disease is difficult due to the propensity for ovarian cancer to disseminate throughout the peritoneum. Currently, there is no single accurate test to detect primary or recurrent ovarian cancer. We report a novel clinical strategy using PPF: a multimodal, PET and optical, folate receptor (FR)-targeted agent for ovarian cancer imaging. The capabilities of PPF were evaluated in primary human ovarian cancer cells, in vivo xenografts derived from primary cells and ex vivo patient omemtum, as the heterogeneity and phenotype displayed by patients is retained. Primary cells uptake PPF in a FR-dependent manner demonstrating approximately a 5- to 25-fold increase in fluorescence. By both PET and fluorescence imaging, PPF specifically delineated FR-positive, ovarian cancer xenografts, with similar tumor-to-background ratios of 8.91±0.91 and 7.94±3.94, and micro-metastatic studding (<1mm), which demonstrated a 3.5-fold increase in PPF uptake over adjacent normal tissue. Ex vivo patient omentum demonstrated selective uptake of PFF by tumor deposits. The ability of PPF to identify metastatic deposits <1mm could facilitate more complete debulking (currently, optimal debulking is <10mm residual tumor), by providing a more sensitive imaging strategy improving treatment planning, response assessment and residual/recurrent disease detection. Therefore, PPF is a novel clinical imaging strategy that could substantially improve the prognosis of patients with ovarian cancer by allowing pre-, post- and intra-operative tumor monitoring, detection and possibly treatment throughout all stages of therapy and tumor progression.

Expression of folate receptor-α (FRA) in gynecologic malignancies and its relationship to the tumor type.

An immunohistochemical evaluation for folate receptor-α (FRA) was undertaken to evaluate expression in gynecologic malignancies involving ovary, endometrium, and the fallopian tube. Commercial tissue microarrays were assessed using an optimized manual immunohistochemical method using MAb 26B3, a newly described monoclonal antibody. A positive result was defined as ≥5% of the sample demonstrating membranous staining. A semiquantitative staining algorithm, defined as the M-score, was used to analyze staining intensity between sample histotypes. MAb 26B3 showed uniform membranous staining and high levels of expression of FRA in ovarian, fallopian tube, and endometrial cancers. All serous ovarian cancers analyzed (70) were positive for FRA expression and no relationship to stage or grade was found. However, a significant difference for FRA expression, between serous and mucinous ovarian carcinomas, was demonstrated (P=0.014). In addition, approximately 90% of all endometrial adenocarcinomas were positive for FRA expression but, unlike ovarian serous carcinomas, a statistically significant relationship to grade was observed (P=0.0029). Although normal ovary is completely devoid of FRA immunoreactivity, normal fallopian tube and cortical serous/tubal inclusion cysts demonstrated uniform and intense FRA staining of columnar epithelium supporting the hypothesis that serous ovarian carcinoma is similar to the tubal epithelium. The data presented further support the hypothesis that FRA expression in gynecologic tumors is due to the cell of origin normally expressing this receptor. This is possibly due to an associated growth advantage, rather than the process of tumorigenesis resulting in aberrant expression of FRA per se.

Self-assembly of folate onto polyethyleneimine-coated CdS/ZnS quantum dots for targeted turn-on fluorescence imaging of folate receptor overexpressed cancer cells.

Folate receptor (FR) can be overexpressed by a number of epithelial-derived tumors, but minimally expressed in normal tissues. As folic acid (FA) is a high-affinity ligand to FR, and not produced endogenously, development of FA-conjugated probes for targeted imaging FR overexpressed cancer cells is of significance for assessing cancer therapeutics and for better understanding the expression profile of FR in cancer. Here we report a novel turn-on fluorescence probe for imaging FR overexpressed cancer cells. The probe was easily fabricated via electrostatic self-assembly of FA and polyethyleneimine-coated CdS/ZnS quantum dots (PEI-CdS/ZnS QDs). The primary fluorescence of PEI-CdS/ZnS QDs turned off first upon the electrostatic adsorption of FA onto PEI-CdS/ZnS QDs based on electron transfer to produce negligible fluorescence background. The presence of FR expressed on the surface of cancer cells then made FA desorb from PEI-CdS/ZnS QDs due to specific and high affinity of FA to FR. As a result, the primary fluorescence of PEI-CdS/ZnS QDs adhering to the cells turned on due to the inhibition of electron transfer. The most important merits of the developed probe are its simplicity and the effective avoidance of the false positive results due to the simple electrostatic self-assembly of FA onto the surface of PEI-CdS/ZnS QDs and the involved fluorescence "off-on" mechanism. The probe was demonstrated to be sensitive and selective for targeted imaging of FR overexpressed cancer cells in turn-on mode.

Protein detection based on small molecule-linked DNA.

Based on small molecule-linked DNA and the nicking endonuclease-assisted amplification (NEA) strategy, a novel electrochemical method for protein detection is proposed in this work. Specifically, the small molecule-linked DNA (probe 1) can be protected from exonuclease-catalyzed digestion upon binding to the protein target of the small molecule, so the DNA strand may hybridize with another DNA strand (probe 2) that is previously immobilized onto an electrode surface. Consequently, the NEA process is triggered, resulting in continuous removal of the DNA strands from the electrode surface, and the blocking effect against the electrochemical species [Fe(CN)(6)](3-/4-) becomes increasingly lower; thus, increased electrochemical waves can be achieved. Because the whole process is activated by the target protein, an electrochemical method for protein quantification is developed. Taking folate receptor (FR) as an example in this work, we can determine the protein in a linear range from 0.3 to 15 ng/mL with a detection limit of 0.19 ng/mL. Furthermore, because the method can be used for the assay of FR in serum samples and for the detection of other proteins such as streptavidin by simply changing the small molecule moiety of the DNA probes, this novel method is expected to have great potential applications in the future.

Folate-binding protein in milk: a review of biochemistry, physiology, and analytical methods.

Folate-binding protein (FBP) was discovered in cow's milk around 40 years ago. Bovine FBP belongs to a family of several folate-binding proteins. In milk, it is a soluble whey protein with the ability to sequester folate from blood plasma. Bovine FBP is a well-characterized protein in terms of amino acid sequence and binding characteristics. Affinity and binding kinetics towards various folate forms have been intensively studied because they are crucial in using bovine FBP as an analytical tool. Shortly after the identification of bovine FBP, a competitive protein-binding assay for measuring serum and blood folate concentrations was introduced. Another analytical application of bovine FBP is in affinity chromatography, as a clean-up/concentration step for analysis of folates in foods and biological samples by liquid chromatographic methods. Concentrations of FBP in milk and dairy products have been determined by ELISA and Surface Plasmon Resonance-biosensor techniques. Since the initial reports of FBP in cow's milk, its physiological role has been discussed, especially regarding its effects on folate absorption from milk and dairy products. This review summarizes recent biochemical, analytical, food science, and nutritional advances regarding folate-binding protein in milk.

The diagnostic and molecular characteristics of malignant mesothelioma and ovarian/peritoneal serous carcinoma.

Malignant mesothelioma and ovarian/peritoneal serous carcinoma are two of the most common tumours affecting the serosal cavities. Unlike other malignant tumours diagnosed at this anatomical site, such as lung and breast carcinoma, malignant mesothelioma and serous carcinoma share a common histogenesis, may be difficult to differentiate morphologically, and co-express many of the diagnostic markers used by cytopathologists in effusion diagnosis. Selected markers have nevertheless shown sufficient sensitivity and specificity to differentiate serous carcinoma from malignant mesothelioma effectively. Recently, our group applied high throughput technology to the identification of new markers that may aid in differentiating these two cancer types and validated several of these markers in follow-up studies. This review will present current data regarding the diagnostic and biological aspects of malignant mesothelioma and ovarian/peritoneal serous carcinoma.