Long-term exposure to commercially available sunscreens containing nanoparticles of TiO2 and ZnO revealed no biological impact in a hairless mouse model

Table 2 Histological findings for all treatment groups from Series 1 and Series 2

	Group ID	Sunscreen	UVR kJ/m²	Number of mice per group	Number of mice that reached endpoint without AE	Total mice with AE	Mice with AE related to malignant or pre-malignant findings (histologically diagnosed)	Mice with AE related to non-malignant findings (histologically diagnosed)	Mice with AE, no necroscopy	Total mice at predetermined endpoint with malignant findings (histologically diagnosed)	Total mice at predetermined endpoint with non-malignant findings (histologically diagnosed)	Total mice at predetermined endpoint with no malignant or non-malignant findings
Series 1	Control-UVR	None	0	10	10	0	0	0	0	0	0	10
	Control + UVR	None	29	10	6	4	4 (1 X CFS; 1 X CFS + SCC; 1 X LL; 1 X SCP)	0	0	1 (1 X SCP)	4^a	1
	ZnO-UVR	ZnO	0	10	10	0	0	0	0	0	1 (1 X PA)	9
	ZnO + UVR	ZnO	29	10	5	5	1 (1 X LL)	2 (1 X N; 1 X HC)	2	1 (1 X CFS)	0	4
	TiO₂-UVR	TiO₂	0	10	9	1	0	1 (1 X P)	0	0	0	9
	TiO₂ + UVR	TiO₂	29	10	10	0	0	0	0	2 (2 X BAC)	1 (1 X PA)	7
	Organic-UVR	Organic	0	10	9	1	1 (1 X LL)	0	0	0	0	9
	Organic + UVR	Organic	29	10	9	1	0	0	1	1 (1 X LL)	0	8
Series 2	2-Control-UVR	None	0	10	10	0	0	0	0	0	0	10
	2-Control + UVR	None	27	10	9	1	1 (1 X LL)	0	0	7 (1 X BAC; 4 X SCC; 1 X LL; 1 X CFS & SCP)	0	2
	2-ZnO-UVR	ZnO	0	10	9	1	1 (1 X LL)	0	0	1 (1 X OS)	0	8
	2-ZnO + UVR	ZnO	27	10	9	1	0	1 (1 X E)	0	0	0	9

The predetermined endpoint for both groups was 36 weeks
CODE: AE adverse event, BAC bronchioalveolar carcinoma, CFS cutaneous fibrosarcoma, E endometritis, HC haemolytic crisis, LL lymphocytic lymphoma, N nephropathy, OS osteosarcoma, P peritonitis, PA pulmonary adenoma, SCC squamous cell carcinoma, SCP squamous cell papilloma
^aNo malignant or non-malignant outcomes, but moderate to severe dermal hyperplasia and inflammation were histologically diagnosed in all four mice

ISSN: 1743-8977