Table 3.

Main Characteristics of the in vivo Studies

Author, Year	Study Design	Location	Samples Characteristics			Calciferol			Other Outcomes
			Included Sample	Sample Size	Obser-Vational Period	Vitamin D Derivate	Dose/Fre-Quency	Administration Method
Makarova, 201722	In vivo study	USA	Murine or mice, with basal cell carcinoma	N/A	N/A	Topical vitamin D3	0.38 µg and 3.8 µg	Topical administration	Low dose of vitamin D3 (0.38 µg) reduced BCC numbers from 6 ± 1.9 to 4 ± 1.4 BCCs/mm skin; High dose of vitamin D3 (3.8 µg) reduced µBCC numbers from 3 ± 1.1 to 0.9 ± 0.5 BCCs/mm skin (p-value=0.0002).
Skobowiat, 201717	In vivo study	USA	Human melanoma cell lines (SKMel-188) and age-matched immunocompromised mice injected with luciferase-labelled SKMel-188 cells	N/A	N/A	20(OH)D3	Dose-dependent insertion; matched volume of either 30 μg/day of 20(OH)D3 diluted in vehicle (25% propylene glycol in distilled water), per animal. Ten doses in total, 5 days per week, were applied for 2 weeks.	Seeded into each well; intraperitoneal injection	20(OH)D3 showed higher efficacy in absolute percentage of inhibition when comparing the inhibition at 10–7 M to that of 1,25(OH)2D3 (56.0% vs 17.0%, respectively for colonies >0.1 mm and 53.1% vs 46.6%, respectively, for colonies >0.2 mm); in the in-vivo study, the accrued tumor volume was 262.35 mm3 in the 20(OH)D3-treated group versus 674.11 mm3 in the vehicle-treated group, representing a 61% decrease in tumor volume.
Spath, 201718	In vivo study	Italy	Melanoma cell lines; and mice injected with melanoma cells	N/A	6 Weeks	1α-OH-vitD3	In the in-vitro study, the concentration ranged from 0.08 µg to 0.8 µg/mL; in the in-vivo study, the dose were as follows: 4 IU; 12 IU	Seeded into each well; gavage feeding for in-vivo study	Significant inhibition in cell proliferation and viability after vitamin D3 exposure to each cell line, with permanent effect after 9-days of exposure. In the in-vivo study, there was a reduction of tumor mass compared to the placebo
Kim, 201623	In vivo study	Korea	Female hairless mice (aged 6–7 weeks)	35	26 weeks	Calcitriol	Calcitriol 3 µg/g	Topical administration (ointment)	Tumors less than 3 mm in size tended to be fewer by 2 to 5 in calcitriol group on average, statistically significant at the 21st week. The number of tumors more than 3 mm in size were significantly fewer in the calcitriol group compared to control group at the 25th week.
Pommergaard, 201424	In vivo study	Denmark	Female SKH-1 hairless mice induced with UVB-light to produce skin lesions resembling squamous cell carcinoma with a dose of 30 mJ/m2	96	17 weeks	Calcitriol, with combination of diclofenac, DFMO, and 5-FU	Calcitriol 0.166 µg/week (50 µg/g undiluted)	Topical administration
Pommergaard, 201325	In vivo study	Denmark	Female SKH-1 hairless mice induced with UVB-light to produce skin lesions resembling squamous cell carcinoma with a dose of 30 mJ/m2	160	17 weeks	Diclofenac plus calcipotriol; DFMO plus calcitriol; and diclofenac plus DFMO plus calcipotriol	Calcitriol 0.166 μg/week (50 μg/g undiluted),	Topical administration