Cancer cells as alternative source of hormones?

The age of Biotechnology has allowed us to introduce foreign genes into micro-organisms and engineer them to produce the substances that we need. It's the first time when scientists can engineer bacteria to produce insulin hormone. There are certain problems with the use of unrelated microorganisms like bacteria. First and foremost, bacteria may lack the post-translational machinery that may be important in providing post-translational modifications to the polypeptide. There is also the issue of codon bias, although expression of foreign genes should work fine in E. coli and S. cerevisiae.

Coming from a cancer research background, I always thought that cancer cells are the best candidates for production of hormones. This is because they retain the eukaryotic translational machinery that allows the polypeptide to fold and also for the expressed polypeptide to be modified post-translationally. Secondly, they overproduce the hormones. A number of subtype of cancers, especially cancer of hormonal glands results in the overproduction of hormones. For instance, thyroid adenoma is known to secrete thyroid hormone. Insulinoma, the cancer of the exocrine pancreas leads to the overproduction of insulin. Tumors also can produce estrogen hormone (Kirschner et al, 1981). Pituitary tumors produce produce massive amounts of growth hormones (Vierimaa et al, 2006).

I figure it would be less of a hassle and opportunity cost to harvest relevant tumor samples from patients and coax them to grow exponentially in culture flasks and produce the precious hormones for therapeutic purpose. Tumor cells are known to be hardy and enjoy the status of immortality even in the culture flask. What's more a single cell can overproduce the hormone in large quantities. No need to do genetic engineering and the related cumbersome process of extracting the gene, ligating it into a vector, transforming the bacteria and then producing the wanted product. Sometimes, the scourge of Mankind can be harnessed to Man's benefit.

Citations
1) Kirschner MA, Lippman A, Berkowitz R, Mayrer E, Drejka M. Estrogen production as a tumor marker in patients with gonadotropin-producing neoplasms. Cancer Res. 1981 Apr;41(4):1447-50.

2) Vierimaa O, Georgitsi M, Lehtonen R, Vahteristo P, Kokko A, Raitila A, Tuppurainen K, Ebeling TM, Salmela PI, Paschke R, Gundogdu S, De Menis E, Makinen MJ, Launonen V, Karhu A, Aaltonen LA. Pituitary adenoma predisposition caused by germline mutations in the AIP gene. Science. 2006 May 26;312(5777):1228-30.

3) Resource on pancreatic cancer. Accessible at http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/pancreatic_cancer_endocrine.jsp

4) Resource on thyroid tumors. Accessible at http://cancer.stanford.edu/endocrine/thyroid/