In addition to oleander, I consider inositol/IP6 as a potentially essential part of an effective anti-cancer protocol. Besides practical experience and numerous first hand testimonials I have heard, here are a few selected studies that may provide insight as to why I like it so much:

Dramatically increases natural killer cell activity.  Anticancer Res. 1999;19:3733-3736. Jariwalla RJ. Inositol Phosphorus (from calcium magnesium phytate
http://www.patient.integrativeinc.com/Products/Critical-Cellular-Support/Pros... 
Integrative Therapeutics - 75802-Cellular Fort with IP-6 and Inositol
A striking anticancer effect of IP6 was demonstrated in different experimental models. Inositol is also a natural constituent possessing moderate anticancer activity.
http://www.ncbi.nlm.nih.gov/pubmed/14608114 
Cancer inhibition by inositol hexaphosphate (IP6) and inositol: from Inositol hexaphosphate ( IP-6, phytic acid, or phytate reported to have in vivo and in vitro anti- cancer activity the molecular mechanisms underlying this anticancer
http://www.raysahelian.com/ip-6.html 
IP-6 : by Ray Sahelian, M.D., inositol hexaphosphate IP-6 and cancer
of food products useful for the treatment of phytate renal calculi (F. Grases, A. Costa-Bauza, Anticancer Res to bond to intestinal amylase reducing the activity thereof
http://www.freshpatents.com/Use-of-germ-flour-of-certain-fruits-for-the-manuf...
myo-inositol and phytate might both protect against fatty liver resulting from Inositol hexaphosphate has broad anticancer activity
http://www.patienthealthyself.info/inositol_hexaphosphate.html
inositol_hexaphosphate
In addition to its antioxidant activity, phytate has shown a lipid-lowering effect in rats Anticancer Res 1999;19:3699-702. Harland BF, Oberleas D. Phytate in foods
http://www.ajcn.org/cgi/content/full/81/3/590 
Phytate: impact on environment and human nutrition. A challenge for The study shows that the low-phytate group differed from the high-phytate group IP6 has anticancer activity against models of breast,colon,liver,prostate, and hematologic http://wholehealthsource.blogspot.com/2009/03/reversing-tooth-decay.html
A strong anticancer activity of IP 6 was also demonstrated against human rhabdomyosarcoma RD cells Harland, B. F. & Oberleas, D. (1987) Phytate in foods. World Rev. Nutr. Diet. 52
http://jn.nutrition.org/cgi/content/full/133/11/3778S
Cancer Inhibition by Inositol Hexaphosphate (IP6) and Inositol: From Preliminary research suggests that glutathione might have anticancer activity by binding with IP-6 (also called inositol hexaphosphate, phytate, or phytic acid) is found in many
http://www.naturesbounty.com/vf/healthnotes/HN77/HN77_English/Concern/Cancer_...
Anti-angiogenic activity of inositol hexaphosphate (IP6) -- Vucenik et
Preliminary research suggests that glutathione might have anticancer activity by binding with IP-6 (also called inositol hexaphosphate, phytate, or phytic acid) is found in many
http://www.prevention.com/cda/vendorarticle/colon-cancer/NW149/health/conditi...
In vivo and in vitro studies utilizing IP6 have revealed a significant anticancer activity with a rats fed both standard rodent chow (low in saturated fat) plus monopotassium phytate
http://www.thorne.com/altmedrev/.fulltext/7/3/244.pdf 
Inositol Hexaphosphate
There is some epidemiologic data suggesting that dietary phytate may have chemopreventive activity. Vucenik I, Kalebic T, Tantivejkulk, Shamsuddin A. Novel anticancer
http://170.107.206.70/drug_info/nmdrugprofiles/nutsupdrugs/ino_0333.shtml
Cancer Inhibition by Inositol Hexaphosphate (IP6) and Inositol: From Selected derivatives were processed for in vivo anticancer activity in human xenograft models. Synthesis and Anticancer Effect of Phytate Containing Pt(II) Complexes Loren D
http://www.jsps.go.jp/j-bilat/semin/gan_report/2005_cancer/01_odani.html