Final answer:
The translocation between immunoglobulin and proto-oncogene loci in myelomas leads to the activation of oncogenes, causing uncontrolled cell growth and potentially leading to cancer.
Step-by-step explanation:
The consequence of translocation between immunoglobulin loci and proto-oncogene loci in myelomas is B) Activation of proto-oncogenes. This genetic alteration can lead to the overexpression of the oncogene, which can then alter transcriptional activity and induce uncontrolled cell growth, a hallmark of cancer. These oncogenes, when activated, can transform normal cells into cancerous cells, resulting in diseases such as Burkett's lymphoma, where the myc protein is aberrantly activated and causes aggressive tumor growth.