It should be noted that according to a recently published study, there are at least 1849 human transcripts that can be translated by alternate ATG initiation codons. Its 62 amino-terminal portion bears no similarity with the previously characterized RNase k-01 isoform or other human proteins, whereas the 63–134 region is absolutely identical to the major part of RNase k-01. Based on this amino-acid sequence, we managed to produce and purify an RNase k-02 specific polyclonal antibody. By the means of our newly developed antibody we were able to demonstrate the biogenesis of the RNase k-02 protein resulting from the RNase k02 mRNA translation in human cells. This alternative protein isoform bears a cytoplasmic topology. To our knowledge, this is the first instance of a human protein isoform encoded by a D4 subtly alternatively spliced transcript. The finding that RNase k-02 protein isoform is detected only in the detergent-insoluble fraction of cell extracts after Triton X-114 phase separation is in agreement with the predicted highly hydrophobic nature of this protein. This fact, in combination with its cytoplasmic localization, supports the hypothesis that RNase k-02 could participate in the formation of macromolecular complexes in vivo or localize in membranic structures such as the endoplasmic reticulum. It is well established that prostate cancer is dependent on androgens. Therefore, androgen deprivation has been the main treatment for advanced prostate cancer. With this therapy, however, the disease rapidly progresses to androgen-independent prostate cancer in most patients. Currently, there are no effective long-term therapies for AIPC. Developing new treatment strategies for AIPC remains attractive but is a challenging problem in clinical oncology. Previous studies have shown that the growth of AIPC is dependent on the androgen receptor. Thus, blocking AR expression has great potential for the treatment of AIPC. Studies have demonstrated that suppressing AR expression with RNA interference technology is an effective way to inhibit the growth of prostate cancer cells, indicating that this method may have the potential to overcome hurdles associated with AIPC treatment. In our previous studies, AR double-stranded RNA with a high specificity for AR genes was designed to block the expression of AR in AIPC cells and to inhibit cell growth. However, this type of gene therapy approach is difficult to apply in a clinical setting due to low gene transfection efficiency. One of the key reasons for low transfection efficiency is the lack of an effective, noninvasive in vivo targeted gene delivery system. In recent years, ultrasound-destructible microbubbles have been shown to be a promising method for gene therapy. Indeed, ultrasound-mediated microbubble destruction can not only improve gene transfection efficiency but can also be used for the tissue-specific delivery of therapeutic agents.