# Moving towards Personalized Medicine--The Broad Use of Aptamers for Targeted Theranostic
## 2 Cancer Therapeutics
Aptamer XQ-2d enables the conjugate to specifically recognize and enter PDAC cells, minimizing its side-effects on normal tissues. XQ-2d-His-SH2 CM-(Arg)9 conjugate impairs the ability of pancreatic cancer cells to undergo epithelial-mesenchymal transition (EMT), inhibiting the proliferation, invasion, and metastasis of PDAC cells [54]. SQ2, is an RNA aptamer with the capacity to be internalized by tumoral cells through ALPPL2-mediated clathrin-independent pathways [55]. This aptamer is capable of carrying a cytotoxic drug, demonstrating potential applications in imaging and therapeutics for all cancers that have aberrant expression of ALPPL2 [55; 56]. The aptamers (1 and 146) colocalized with existing Cancer Stem Cell (CSC) markers, such as CD44, CD24, EpCAM, and CD133, which can recognize CSC marker-enriched Circulating Tumor Cells (CTCs) in pancreatic cancer, suggesting potential applications in pancreatic cancer diagnosis and treatment [57]. The X-aptamer targeting the Thy-1 membrane glycoprotein (THY1), overexpressed in pancreatic cancer cells, provides a non-immunogenic and specific option in the context of biomarker development and clinical application [58]. Additionally, some other aptamers are being tested. The aptamer aptacy binds to the TfR, leading to an enhancement in the therapeutic response of Doxorubicin [59]; NOX-E36 aptamer connects to CCL2 and can be used not only in pancreatic tumors, but also in Diabetes mellitus type 2 (T2 DM) [60]; cancer cell secretome can be detected and differentiated from healthy cells using the cyclophilin B aptamer [61]; the P12 FR2 aptamer binds to PAUF and reduces the growth and metastatic capacity of cancer cells [62]; the use of NOX-A12, which targets CXCL12, leads to the reduction in cell adhesion and signaling processes, as well as cancer cell growth and proliferation [63]. Aside from the specificity for cancer sites, there are some aptamers that are not specific to target tissues, but cancer cells. The aptamers 4-1 BB, which targets TNFSF9 [64], and OX40, which binds to TNFSF9 [65], promote immunotherapy treatment. GL21.T is another aptamer which allows the improvement of cancer cells to endocytose drugs, as well as to promote tumor selectivity [66]; Two different aptamers, Apt-siRNA [67] and CAR-like multivalent aptamer [68], do not have a specific target, although they have the capacity to lead to anticancer effects; bi-functional aptamers target opsonin C3b/iC3b, resulting in cancer cell destruction [69]; the AS1411 aptamer and cyclic peptide RGD bind to Alpha-v beta 3 (\(\alpha\)vv\(\beta\)3), inhibiting cell growth and proliferation [70]; the H02 aptamer targets \(\alpha\)5\(\beta\)1, reducing invasion capacity [71]; and dox-incorporated multivalent aptamer-siRNA conjugates produce powerful anticancer effects [72]. Conversely, tumor cells express shared tumor-specific antigens, which can induce immune responses when presented with MHC molecules on the cell surface. MAGE-A3 is a tumor-specific antigen that is highly expressed in several types of cancer, including melanoma, esophageal carcinoma, gastric carcinoma, multiple myeloma, breast cancer, and pancreatic cancer, often associated with malignancy and poor prognosis. [PERSON] et al. (2016) described a DNA aptamer against the shared tumor-specific antigen MAGE-A3, which discriminates multiple types of cancer cells from normal cells (Ap52) [73]. In 2021, [PERSON] and his team demonstrated that Ap52 can effectively penetrate cancer cells and selectively deliver the anticancer drug Doxorubicin (Dox), causing cytotoxicity to multiple types of cancer cell, becoming a promising therapeutic delivery system for various tumors [74]. In addition, aptamers may provide combinatorial manipulation of cell immunity and drug targeting for cancer therapy, and a combination of aptamers targeting various shared tumor-specific antigens may be used to combat tumor heterogeneity [74; 77].