**6. Immunotherapy for CTVT treatment**

Recently, researchers have found that inflammation and epithelial cell proliferation may characterize the early response to VCR treatment in the early stage [40]. CTVT in the R-phase after treatment showed that the expression of many groups of genes occurred at the same time, with pathological changes of not only macroscopic features but also microscopic ones. The group of inflammation genes was the most upregulated in the S-phase, and the immunologic groups of genes involved in T-cell, NK-cell, and B-cell function were upregulated in the R-phase. In this late R-phase, there was a loss of CTVT cells and cell migration but an increase in fibrosis that is related to new tissue formation or the healing stage [23, 40]. This finding revealed the process that started with the inflammatory response, epithelial and keratinocyte proliferation and followed by the host T-, NK- and B-cell infiltration, and finished with the cell cycle arrest. In addition, Bcell-related genes, albeit less prominent in quality and expression levels than T- and NK-cell panels, were also progressively upregulated [40]. This is related to previous studies that showed that the infiltration and presence of B-cell was the signature of acute allograft rejection [41].

The interferon (IFN) for neoplasia treatment is initially based on the nonspecific activating host immune response. Normally, type I IFN has the ability to inhibit tumor cell growth and induce tumor cell apoptosis in the in vitro studies [42]. During the R-phase of CTVT growth, the IL-6 and interferon-γ or Type II IFN from the host plays a special role in enhancing MHC molecule expression on antigen-presenting cells, activating NK-cell activities, and modulating B lymphocyte responses [20, 37, 43]. An in vitro study of interferon type I for CTVT treatment found that interferon ω showed the effect of inhibiting CTVT cell viability in a dose-dependent manner [44]. CTVT case treatment by immunotherapy is of interest to many researchers. Recently, the combination protocol of intratumoral interferonα2a with VCR shortened the treatment duration when compared with VCR alone [45]. Thus, combining a low-dose chemotherapeutic drug and immunotherapy may be advantageous for CTVT patients because of the initial trigger of inflammation by chemotherapy, synergizes with the activation of the host immune response by interferon. The VCR triggers host interferon signal expression, which induce NK-cell and lymphocyte infiltration. The addition of interferon may enhance the innate and adaptive responses of mononuclear cells and might affect CTVT viability and proliferation. The change in environment and the increase in inflammatory production by local host cells after treatment with VCR may trigger and recruit immune cells. The strong response induced by VCR causes the release of damage-associated molecular patterns from stressed or apoptotic cells as an innate immune response of the host, which induces direct cognition of foreign DLA molecules and ultimately leads CTVT to regression. In addition, this evidence suggests that combining the low dose of chemotherapy with immune checkpoint therapy may help the host immune response against CTVT by inducing the inflammation for tumor regression (**Figure 4**) [40].

#### **Figure 4.**

*Histopathologic features of CTVT tissue at week 0 or before treatment with vincristine (4A) and two weeks after treatment (4B).*
