Oncogenic viruses: The viruses that can achieve neoplastic transformation are traditionally referred to as what?

Introduction / Context:
Oncogenic (cancer-causing) viruses can transform host cells to a neoplastic state. Historically, distinct terms were used for DNA-based and RNA-based tumor viruses. This item probes that terminology and the classic association of retroviruses with oncogenesis.

Given Data / Assumptions:

• Retroviruses possess RNA genomes and reverse transcriptase.
• Many classic animal tumor models involved retroviruses.
• DNA viruses (e.g., papillomaviruses, polyomaviruses) can also be oncogenic but were classed separately as DNA tumor viruses.

Concept / Approach:
Historically, “RNA tumor viruses” was the term for retroviruses that induce tumors (e.g., Rous sarcoma virus). While DNA tumor viruses exist, the phrasing “the viruses that can achieve neoplastic transformation are called” aligns best with the classical term describing RNA-based tumor viruses. Note: HIV is a retrovirus but is not classically classified as an RNA tumor virus because it is not typically transforming.

Step-by-Step Solution:
Identify the traditional nomenclature used in virology texts.Recognize that RNA tumor viruses refers to retroviruses associated with oncogenesis.Choose the option that matches this established term.

Verification / Alternative check:
Classic literature distinguishes RNA tumor viruses (retroviruses) from DNA tumor viruses; both can transform, but the term in common use for RNA-based transforming viruses is “RNA tumor viruses.”

Why Other Options Are Wrong:

• DNA tumor viruses (A): can be oncogenic, but the singular phrasing of the question points to the classic term for retroviruses.
• retroviruses HIV (C): HIV is a retrovirus but not a prototypical transforming virus.
• none of these (D): incorrect because “RNA tumor viruses” is a recognized term.

Common Pitfalls:
Assuming all retroviruses are tumorigenic or equating HIV with tumor viruses; HIV is immunosuppressive rather than directly transforming.

Final Answer:
RNA tumor viruses