With available MRI techniques, primary and metastatic liver cancers that are associated with high mortality rates and poor treatment responses are only diagnosed at late stages, due to the lack of highly sensitive contrast agents without Gd 3+ toxicity. We have developed a protein contrast agent (ProCA32) that exhibits high stability for Gd 3+ and a 10 11 -fold greater selectivity for Gd 3+ over Zn 2+ compared with existing contrast agents. ProCA32, modified from parvalbumin, possesses high relaxivities (r 1 /r 2 : 66.8 mmol −1 ·s −1 / 89.2 mmol −1 ·s −1 per particle). Using T 1 -and T 2 -weighted, as well as T 2 /T 1 ratio imaging, we have achieved, for the first time (to our knowledge), robust MRI detection of early liver metastases as small as ∼0.24 mm in diameter, much smaller than the current detection limit of 10-20 mm. Furthermore, ProCA32 exhibits appropriate in vivo preference for liver sinusoidal spaces and pharmacokinetics for high-quality imaging. ProCA32 will be invaluable for noninvasive early detection of primary and metastatic liver cancers as well as for monitoring treatment and guiding therapeutic interventions, including drug delivery.MRI | uveal melanoma | metastasis | contrast agents | T 2 /T 1 ratio imaging T umor metastasis is the main cause of nearly all human cancerrelated deaths. Liver is a common site for metastases of a variety of cancers, including melanoma, breast, pancreatic, and colon cancers (1, 2). For example, uveal melanoma, the most common primary intraocular tumor, has a 40% risk of metastasizing to the liver within 10 y of diagnosis of the primary tumor. Hepatic metastases, which occur in 95% of patients with uveal melanoma metastasis, result in death in almost all cases. This high death rate is related to the recognition of liver metastasis at a late clinical stage (at stage II or later in the TNM system) in which the metastatic uveal melanoma is resistant to currently available systemic chemotherapies (3, 4). The liver may also give rise to primary tumors such as hepatocellular carcinoma (HCC), which is the most common primary malignancy worldwide (5). However, currently there is no reliable way to detect primary liver cancer and hepatic metastases at early stages with high sensitivity and specificity.MRI is a widely used clinical imaging modality that provides exquisite soft-tissue contrast without using ionizing radiation (6, 7). More than 35% of MRI scans use MRI contrast agents, particularly paramagnetic gadolinium (Gd 3+ )-based contrast agents, which shorten T 1 and lead to an increase in MRI intensity (8). All clinically approved Gd 3+ -containing contrast agents are based on small chelators with relaxivity (r 1 and r 2 ) values around 4-6 mM −1 ·s −1 . Their low relaxivities severely limit the sensitivity of current MR imaging methods with respect to detection of lesions and treatment planning and monitoring. Repeat MRI scans are frequently requested for patients with ambiguous small lesions and are used as a routine follow-up modality for highrisk patients, but t...

Early diagnosis and noninvasive detection of liver fibrosis and its heterogeneity remain as major unmet medical needs for stopping further disease progression toward severe clinical consequences. Here we report a collagen type I targeting protein-based contrast agent (ProCA32.collagen1) with strong collagen I affinity. ProCA32.collagen1 possesses high relaxivities per particle (r1 and r2) at both 1.4 and 7.0 T, which enables the robust detection of early-stage (Ishak stage 3 of 6) liver fibrosis and nonalcoholic steatohepatitis (Ishak stage 1 of 6 or 1 A Mild) in animal models via dual contrast modes. ProCA32.collagen1 also demonstrates vasculature changes associated with intrahepatic angiogenesis and portal hypertension during late-stage fibrosis, and heterogeneity via serial molecular imaging. ProCA32.collagen1 mitigates metal toxicity due to lower dosage and strong resistance to transmetallation and unprecedented metal selectivity for Gd3+ over physiological metal ions with strong translational potential in facilitating effective treatment to halt further chronic liver disease progression.

Background: It is known that PKM2 is present in cancer patient blood. It is not known if PKM2 functions in cancer progression. Results: PKM2 in blood facilitates tumor growth by promoting tumor angiogenesis via increasing angiogenic endothelial cell migration and ECM attachment. Conclusion: Extracellular PKM2 promotes tumor angiogenesis. Significance: We reveal a novel mechanism of cancer angiogenesis that could potentially be a new target for anti-angiogenesis.

Prostate-specific membrane antigen (PSMA) is one of the most specific cell surface markers for prostate cancer diagnosis and targeted treatment. However, achieving molecular imaging using non-invasive MRI with high resolution has yet to be achieved due to the lack of contrast agents with significantly improved relaxivity for sensitivity, targeting capabilities and metal selectivity. We have previously reported our creation of a novel class of protein Gd 3+ contrast agents, ProCA32, which displayed significantly improved relaxivity while exhibiting strong Gd 3+ binding selectivity over physiological metal ions. In this study, we report our effort in further developing biomarker-targeted protein MRI contrast agents for molecular imaging of PSMA. Among three PSMA targeted contrast agents engineered with addition of different molecular recognition sequences, ProCA32.PSMA exhibits a binding affinity of 1.1 ± 0.1 μM for PSMA while the metal binding affinity is maintained at 0.9 ± 0.1 × 10 −22 M. In addition, ProCA32.PSMA exhibits r 1 of 27.6 mM −1 s −1 and r 2 of 37.9 mM −1 s −1 per Gd (55.2 and 75.8 mM −1 s −1 per molecule r 1 and r 2 , respectively) at 1.4 T. At 7 T, ProCA32.PSMA also has r 2 of 94.0 mM −1 s −1 per Gd (188.0 mM −1 s −1 per molecule) and r 1 of 18.6 mM −1 s −1 per Gd (37.2 mM −1 s −1 per molecule). This contrast capability enables the first MRI enhancement dependent on PSMA expression levels in tumor bearing mice using both T 1 and T 2 -weighted MRI at 7 T. Further development of these PSMAtargeted contrast agents are expected to be used for the precision imaging of prostate cancer at an † Electronic supplementary information (ESI) available. See

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