Table 3.

Tumor occurrence in GF rats and mice induced with chemical carcinogens.

Induced Tumors	Chemical	Method of Administation	Incidence GF %	Incidence CV %	Main Types of Tumors	Strain	Gender	n. of Animals	Age of Animals at the Start of Experiment	Year	Citation
Rats	DMBA + 15% fat emulsion	intra peritoneal	56%	67%	mammary gland, leukaemia	Sprague-Dawley	♂	18 GF (−2†)	1 month	1967	[36]
								11 (−5†) CV
			100%		myeloid leukaemia	Fisher		18 GF (−16†)
	DMBA in sesame oil	stomach tube	100%	89%	breast	Sprague-Dawley	♀	11 (−2†) GF	2 months	1963	[37]
								29 (−11†)CV
			20%	0%		Fisher	♀	8 GF
								12 CV
			all died because of cytotoxicity	0%		Wistar	♀	15 (−15†) GF
								9 CV
	MCA in olive oil	subcutaneous	79%	82%	fibrosarcoma	Wistar	♀, ♂	14 GF, 11 CV	various	1964	[38]
			96%	87%		Fisher	♀, ♂	27 GF, 39 CV
Mice	MCA in olive oil	subcutaneous	100%	100%	fibrosarcoma	Swiss-Webster	♀, ♂	13 GF, 14 CV	various	1964	[38]
			80%	72%		C3H	♀, ♂	71 GF, 18 CV
			57%			ICR	♀, ♂	33 GF
			76%			CFW	♀, ♂	17 GF
	20-MCA in olive oil	orally	94%		leukaemia	RFX	♀, ♂	48 GF	5–6 weeks	1971	[39]
			27%		lung			49 GF
	20-MCA + croton oil	Orally—topically (abdomen skin)	97%		leukaemia			68 GF
			44%		lung			62 GF
	MCA in olive oil	subcutaneous	100%	89%	lung	Swiss-Webster	♀, ♂	61 GF, 54 CV	newborn	1963	[40]
	Urethane	intra peritoneal	56%	85%	lung	BALB/c	♀	17 GF, 20 CV	6–9 weeks	1970	[41]
			0%	25%		C3H/HeN	♀	4 GF, 20 CV
			0%	27%		C57Bl/6N	♀	10 GF, 22 CV
			0%	14%		C57Bl/6N	♂	3 GF, 22 CV
	mineral oil	intra peritoneal	6%	70%	plasma cell	BALB/c AnN	♀	33 GF, 40 CV	1–2 months	1969	[42]
			6%	5%	pulmonary adenoma
			48%	10%	pleomorfic reticulum sarcoma

Acronym of chemicals. DMBA: 7, 12-dimethylbenz(a)-anthracene; MCA: Methylcholanthrene.