For example, both RASSF1A and p16 are frequently inactivated in human malignancies by methylation changes during malignant conversion (Auerkari 2006; Baylin et al. 1991; Kuzmin et al. 2002; Perry et al. 2006; Wu et al. 2005).
Given the high risk of malignant conversion, surgical resection of the cyst, especially the extrahepatic bile duct, has been recommended for type IV CCs [23, 24].
We suggest that recently identified processes, such as the "bystander effect", might affect initiation, promotion, and malignant conversion in different ways.
Our data identified IFN-γ as a pivotal secreted factor that orchestrates complex changes in inflammatory, epithelial, and mesenchymal cell populations to drive pre-neoplastic progression in stomach; however, additional alterations appear to be required for malignant conversion.
Approximately 15 20% of global cancer incidence is causally linked to viral infection, yet the low incidence of cancers in healthy infected individuals suggests that malignant conversion of virus-infected cells occurs after a long period as a result of additional genetic modifications.
These observations point to an inhibitory effect of VILIP-1 on tumor development, malignant conversion and on tumor progression.
NF-κB activation in those cells leads to the production of cytokines, growth factors, and angiogenic factors that promote malignant conversion and progression (for review see [3]).
This is in contrast to the genesis of many solid tumors which can be traced through a series of well-defined histopathological changes in tissue architecture from a benign tumor through to its malignant conversion.
Besides expression of E6 and E7 genes, additional events such as Ras activation could increase malignant conversion and tumor forming ability of HPV expressing cells [52], [53] and will worth careful investigation in the future.
Our finding that FOXM1 is upregulated early during oral cancer progression renders FOXM1 an attractive diagnostic biomarker for early cancer detection and its candidate mechanistic targets, CEP55 and HELLS, as indicators of malignant conversion and progression.
In our study, CRC were more likely to be proximal, suggesting that if the effect of smoking in patients with multiple serrated polyps is to increase the likelihood of left sided polyps, then our findings that smoking overall has no significant effect on CRC development is consistent with this, as left colon serrated polyps are less likely to undergo malignant conversion.
