Anti-Carcinoembryonic antigen monoclonal antibody, clone NM12D12

Small biomolecules are typically radiolabeled with F-18 by binding it to a carbon atom, a process that usually is designed uniquely for each new molecule and requires several steps and hours to produce. We report a facile method wherein F-18 is first attached to aluminum as (AlF)-F-18, which is then bound to a chelate attached to a peptide, forming a stable (AlF)-F-18-chelate-peptide complex in an efficient 1-pot process. Methods: For proof of principle, this method was applied to a peptide suitable for use in a bispecific antibody pretargeting method. A solution of AlCl3 center dot 6H(2)O in a pH 4.0 sodium-acetate buffer was mixed with an aqueous solution of F-18 to form the (AlF)-F-18 complex. This was added to a solution of IMP 449 (NOTA-p-Bn-CS-D-Ala-D-Lys(HSG)-D-Tyr-D- Lys(HSG)-NH2) (NOTA-p-Bn-CS is made from S-2-(4-isothiocyanatobenzyl)- 1,4,7-triazacyclononane-1,4,7-triacetic acid; HSG is histamine-succinyl-glycine) and heated to 100 degrees C for 15 min. In vitro and in vivo stability and targeting ability of the (AlF)-F-18-IMP 449 were examined in nude mice bearing LS174T human colonic tumors pretargeted with an anti-CEACAM5 bispecific antibody (TF2). Results: The radiolabeled peptide was produced in 5%-20% yield with an estimated specific activity of 18,500-48,100 GBq (500-1,300 Ci)/mmol. The (AlF)-F-18-IMP 449 was stable for 4 h in serum in vitro, and in animals, activity isolated in the urine 30 min after injection was bound to the peptide. Nonchelated (AlF)-F-18 had higher tissue uptake, particularly in the bones, than the chelated (AlF)-F-18-IMP 449, which cleared rapidly from the body by urinary excretion. Tumor uptake was 30-fold higher with TF2-pretargeted (AlF)-F-18-IMP 449 than with the peptide alone. Dynamic PET showed tumor localization within 30 min and rapid and thorough clearance from the body. Conclusion: The ability to bind highly stable (AlF)-F-18 to metal-binding ligands is a promising new labeling method that should be applicable to a diverse array of molecules for PET.

AimTo investigate the clinical and prognostic significance of circulated tumor cells (CTC) marked by cytokeratin 19 coding gene KRT19 mRNA and carcinoembryonic antigen coding gene CEACAM5 mRNA in preoperative peripheral blood of breast cancer patients and provide molecular markers for breast cancer metastasis risk.MethodsThe mRNA levels of KRT19 and CEACAM5 in preoperative peripheral blood of breast cancer patients without (n=603) and with (n=76) distant metastases at the time of initial diagnosis were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The relationship between CTCKRT19, CTCCEACAM5 and clinicopathological features, local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), or overall survival (OS) was statistically analyzed.ResultsIn different pathological stages of breast cancer, the rates of CTCKRT19-pos and CTCCEACAM5-pos increased with the increase of the stages (P=0.077 and P=0.004). Preoperative CTCKRT19-pos in breast cancer patients was closely related to the lymph node metastasis statues (P<0.0001), and had no significant correlation with other clinicopathological features. There was no significant correlation between CTCCEACAM5 and the clinicopathological features. Patients with high levels of CTC double-marked by KRT19 and CEACAM5 mRNA had shorter DMFS (P<0.0001) and OS (P=0.016) for patients with breast cancer. The 7-year DMFS rates for the low-, intermediate-, and high-risk groups were 90.7%, 67.5%, and 59.1%, respectively (P<0.0001). The prognosis of patients with decreased KRT19 and CEACAM5 mRNA after treatment is better than that of patients who have not decreased, and the combination of the two indicators is better than the single one for predicting PFS (P=0.002 compare with P=0.036 or P=0.047).ConclusionDouble-marked CTC by KRT19 and CEACAM5 mRNA is a prognostic index of breast cancer patients before surgery and after chemotherapy. Single-marked CTC by KRT19 mRNA indicates lymph node statues of preoperative patients. Therefore, the RT-qPCR-based molecular diagnosis of CTC could be used for prognostic prediction of breast cancer patients and guiding clinical treatment.