**5. Nanobased cancer diagnosis approaches**

Current problems and unmet needs in translational oncology include (i) advanced technologies for tumor imaging and early detection, (ii) new methods for accurate diagnosis and prognosis, (iii) strategies to overcome the toxicity and adverse side effects of chemotherapy drugs, and (iv) basic discovery in cancer biology leading to new knowledge for treating aggressive and lethal cancer phenotypes such as bone metastasis. Advances in these areas will undoubtedly form the major cornerstones for a future medical practice of personalized oncology. Cancer detection, diagnosis, and therapy will be tailored to each individual's tumor molecular profile and used in predictive oncology, whereby genetic/molecular markers will play an essential role in the prediction of disease development, progression, and clinical outcomes.

The probability of a successful treatment modality increases dramatically if tumor cells can be selectively removed before they evolve to their mature stages and metastases production. As such, novel and more sensitive diagnostic tools like metallic and semiconducting nanoparticles are being developed with the aim of improving the early and noninvasive detection of rising malignancies and the accuracy of tumor tissue localization. Paramagnetic nanoparticles, quantum dots, nanoshells and nanosomes represent some of these new

Construction of organ-targeted gene delivery vectors is a promising route to improve the safety and efficacy of nanomedicine based cancer gene therapy. There are a variety of 'vector targeting' strategies, that can be accomplished using transcriptional targeting, transductional targeting, or ideally, a combination of these. While transcriptional targeting refers to the use of gene regulatory elements (promoters and enhancers) to restrict gene expression to specific cells, transductional targeting refers to the delivery of DNA to specific cells. Targeted gene expression has been analyzed using tissue-specific promoters (breast-, prostate-, and melanoma-specific promoters) and disease-specific promoters (carcinoembryonic antigen, HER-2/neu, Myc-Max response elements, DF3/MUC). The addition of a ligand (i.e., folate, transferrin, RGD peptide, among others) to the nanoparticle surface, thus targeting the DNA to cells *in vivo* has been demonstrated quite successfully*.* Folate-receptor-targeted liposomes have proven effective in delivering doxorubicin *in vivo* and have been found to bypass multidrug resistance in cultured tumor cells (Immordino et al. 2006). Hong et al., (2010) exploited the possibility of combination of the functions of passive and active targeting by transferring-PEGlyated nanoparticles (Tf-PEG-NP), as well as sustained drug release in tumor by PEGylated drug for most efficient tumor targeting and anti-tumor effects enhancement. Such Tf-PEG-NP loaded with PEGylated drug conjugates could be one of the promising strategies in nanomedicine to deliver anti-tumor drugs to tumor (Hong et al. 2010). Further enhancement of the therapeutic index may also be achieved by overcoming barriers both at cellular and nuclear levels. In gene therapy studies, nuclear localization signal peptides have been investigated as facilitators of nuclear transport with the aim of enhancing transgene expression. Selective tumor targeting with minimal toxicity using folate modified, incorporating nuclear localization signal represents a popular approach. In recent years, Poly(εcaprolactone)/poly(ethylene glycol) (PCL/PEG) copolymers which are biodegradable and amphiphilic, are also emerging as a potential nanoplatform for anticancer agent delivery

Current problems and unmet needs in translational oncology include (i) advanced technologies for tumor imaging and early detection, (ii) new methods for accurate diagnosis and prognosis, (iii) strategies to overcome the toxicity and adverse side effects of chemotherapy drugs, and (iv) basic discovery in cancer biology leading to new knowledge for treating aggressive and lethal cancer phenotypes such as bone metastasis. Advances in these areas will undoubtedly form the major cornerstones for a future medical practice of personalized oncology. Cancer detection, diagnosis, and therapy will be tailored to each individual's tumor molecular profile and used in predictive oncology, whereby genetic/molecular markers will play an essential role in the prediction of disease

The probability of a successful treatment modality increases dramatically if tumor cells can be selectively removed before they evolve to their mature stages and metastases production. As such, novel and more sensitive diagnostic tools like metallic and semiconducting nanoparticles are being developed with the aim of improving the early and noninvasive detection of rising malignancies and the accuracy of tumor tissue localization. Paramagnetic nanoparticles, quantum dots, nanoshells and nanosomes represent some of these new

**4.1 Targeted nanomedicine** 

(Gou et al. 2011).

**5. Nanobased cancer diagnosis approaches** 

development, progression, and clinical outcomes.

technologies, used for diagnostic purposes (See Figure 4). Compared to conventional materials, inorganic nanomaterials provide several advantages such as simple preparative processes and precise control over their shape, composition and size. These systems provide promising potential not only in diagnostics, but also as delivery systems for therapeutic agents and are discussed in detail below.

Fig. 4. Nanoparticles used in cancer diagnosis and treatment. Liposomes contain amphiphilic molecules, which have hydrophobic and hydrophilic groups that self-assemble in water. Gold nanoparticles are solid metal particles that are conventionally coated with drug molecules, proteins, or oligonucleotides. Quantum dots consist of a core-and-shell structure (e.g., CdSe coated with zinc and sulfide with a stabilizing molecule and a polymer layer coated with a protein). Fullerenes (typically called "buckyballs" because they resemble Buckminster Fuller's geodesic dome) and carbon nanotubes have only carbon-to-carbon bonds.
