Attentuated Herpesvirus Encoding a Mek Pathway Polypeptide

The disclosure provides materials and methods for the treatment of cells exhibiting a cell proliferative disorder with a herpes simplex virus having a deficiency in the expression of active ICP34.5 and comprising an expression control element effective in modulating at least one component of the MEK pathway to ensure that infected cells are MEK+. Cell proliferative diseases, disorders or conditions, such as cancers, rheumatoid arthritis and macular degeneration, are amenable to treatment using these HSVs. Further provided are methods for preventing such cell proliferative disorders by administering the HSVs as well as methods for ameliorating a symptom associated with a cell proliferative disorder by administering such HSVs.