Table 1.

Postnatal Soy/Isoflavone Administration.

Species	Isoflavone Diet/Timing	Tumor Inducer	Main Finding	Refs
rat	0.25 g/kg or 1 g/kg of daidzein or genistein separately or 1 g/kg of both daidzein and genistein, PND35-EOS	1 oral dose, 80 mg/kg body weight DMBA at PND50	No significant difference in tumor incidence or size compared to control diet	[69]
rat	500 ppm genistein in diet, PND15–30, PND15–30 and PND55-EOS or PND55-EOS	1 oral dose, 10 mg DMBA at PND48	Tumor onset delayed only in group fed genistein PND15–30 and PND55-EOS compared to control diet. No significant difference in tumor incidence	[70]
rat	2 mg/kg body weight, genistein orally, PND42-EOS	1 oral dose, 80 mg/kg body weight DMBA at PND55	Tumor incidence and size significantly reduced in genistein group compared to controls	[71]
rat	3.24 mg total isoflavones/g protein in diet of lean or obese rats, PND42-EOS	1 oral dose, 65 mg/kg body weight DMBA at PND50	Tumor incidence significantly reduced in lean soy fed rats vs lean casein fed rats yet tumor incidence significantly higher in obese soy-fed rats vs obese casein fed rats. No significant differences in tumor onset or multiplicity	[72]
rat	Genistein 20 mg/kg body weight, daidzein 20 mg/kg body weight or genistein + daidzein 20 mg/kg each), oral 1 week before DMBA-EOS	1 injection, 25 mg DMBA, exact age not defined	Genistein alone, daidzein alone and the combination significantly reduced tumor size compared to control mice. Tumor incidence appeared to be reduced, especially in combination group but no significance was indicated.	[73]
rat	Isoflavone-deprived soy peptide, PND28-PND56 and PND63-EOS	1 oral dose, 50 mg/kg body weight DMBA at PND56	Tumor latency was significantly increased, and tumor size and multiplicity were significantly decreased in isoflavone-deprived soy group vs control group	[74]
rat	Soy milk PND50-EOS	1 oral dose, 5 mg DMBA at PND49	Tumor incidence significantly higher in soy milk group compared to water group; no significant differences in tumor multiplicity or size	[75]
rat	20% soy protein, PND25-EOS	1 oral dose, 80 mg/kg body weight DMBA at PND50	Tumor onset significantly delayed, and tumor multiplicity significantly reduced in soy group vs control group but no difference in tumor incidence at study endpoint	[76]
rat	Soy-free diet with 0.35% or 0.7% (w/w) SOYSELECT (12% isoflavones and 35% saponins), PND21-EOS	1 oral dose, 80 mg/kg body weight DMBA at PND50	No significant differences observed at study endpoint	[77]
rat	0.03, 0.4 or 0.81 mg/g diet isoflavones, PND36-EOS	1 oral dose, 10 mg DMBA at PND50	No significant differences in tumor incidence, onset, multiplicity or burden	[78]
rat	200 mg/kg diet genistein, 200 mg/kg diet daidzein, 100 mg/kg diet each of genistein + daidzein, 160 g/kg diet SPI or 160 g/kg diet SPI depleted of isoflavones, PND43-EOS	1 oral dose, 15 mg DMBA at PND50	Tumor multiplicity significantly reduced in daidzein and both SPI diets; no significant difference in tumor incidence, mean latency or size in any of the diets	[79]
rat	1 mg/kg body weight genistein injected daily, PND45-EOS	1 injection, 40 mg/kg body weight NMU at PND45	Tumor multiplicity and size significantly elevated in genistein group vs control group	[80]
rat	0.03 or 1 mg/g of genistein in soy free diet or soy containing basal diet PND28-EOS	Oral, 10−3 M EMS in drinking water, PND28-PND112	no significance difference in tumor incidence, size or latency compared to control group	[81]
rat	100 g soymilk powder/kg diet alone or with 2 g/kg diet Lactobacillus casei in a high fat diet, PND35-EOS.	oral, 85 mg/kg PhIP, 4 x/week for 2 weeks, PND42–56	according to Table 2, no significant differences in tumor incidence, multiplicity or size in soymilk vs control, however Figure 1 indicates that tumor multiplicity significantly reduced at study endpoint. The combination of soymilk and Lactobacillus casei significantly reduced tumor multiplicity	[82]
mouse	Soybean diet (40% soybean meal), PND49-EOS	MMTV-neu, low estrogen (ovariectomy), normal estrogen (untreated), and high estrogen (estradiol injection)	Tumor incidence significantly increased in soy-fed, low estrogen group but tumor incidence significantly reduced in soy-fed, high estrogen group. No significant differences in tumor latency or size	[83]
mouse	21.7% soy protein isolate, PND60-EOS	MMTV-neu (did not consider ERΔ3/neu mice)	No significant effect on tumor incidence or latency in soy-fed MMTV-neu mice compared to MMTV-neu mice fed a control diet	[84]
mouse	0.004%, 0.02% or 0.06% wt/wt Prevastein (46.19% wt/wt isoflavones), PND25-EOS	MMTV-neu fed a Western diet (high fat, moderate fiber, low calcium)	Significant increase in tumor multiplicity and size in highest isoflavone group compared to control group; no differences in medium or low isoflavone group and no significant differences in tumor incidence between any of the groups	[85]
mouse	Purina 5001 (soy diet), PND28-EOS	MMTV-neu implanted with 0.5 mg, 60-day constant release estrogen pellet	Tumor onset significantly delayed in soy group for both placebo and estrogen pellet mice vs control mice; no significance different in tumor incidence was reported	[86]
mouse	250 mg/kg genistein, 250 mg/kg daidzein, NovaSoy, PND56-EOS	MMTV-neu, 1 pregnancy and 2 weeks of lactation	Tumor latency delayed in all isoflavone groups, tumor growth, incidence, multiplicity and size not affected	[87]
mouse	Supro 670 with low or high isoflavone (0.2 and 1.81 mg isoflavone/g protein isolate), PND28-EOS	MMTV-neu on high fat diet	No significant difference in tumor incidence, onset, multiplicity or size	[91]
mouse	430 mg isoflavones/kg diet, PND21-EOS	MMTV-Wnt1	Tumor incidence and latency reduced in isoflavone group	[88]
mouse	250 mg/kg genistein, PND28-EOS	C(3)1-SV40	No effect on tumor incidence or growth rate	[89]
mouse	32 mg/kg or 972 mg/kg isoflavones, PND22-EOS	MT-hGH	Tumor latency reduced, and tumor size increased in high isoflavone group	[90]

PND = post-natal day; EOS = end of study; DMBA = 7,12-Dimethylbenzathracene; NMU = N-methyl-N-nitrosourea; PhIP = 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine.