TABLE 1.

Characteristics of the included studies (Shanghai, China. 2022).

Study ID	Study design	Sample size RB	Sample size control	Definition of control	Age (mean (SD))	RB diagnosis	Male prevalence in RB
[7]-India	Cross-sectional	64	—	—	2.5 years	PCR	NR
[8]-Brazil	Cross-sectional	154	44	Normal retina from each embedded tissue block	22.4 months	PCR	74
[9]-India	Cross-sectional	72	—	—	4 years	PCR	46
[18]-India	Cross-sectional	106	—	—	26.7	PCR	55
[10]-India	Cross-sectional	44	30	Non-neoplastic donor retinas	2 a	PCR	27
[19]-Mexico	Cross-sectional	51	6	Non-RB occular tissue	2 months-8 years b	PCR	NR
[20]-India	Cross-sectional	39	42	Donor eyes obtained from the eye bank	41.8 (26.2)	PCR	20
[21]-Mexico	Cross-sectional	39	—	—	<5 years	PCR	NR
[22]-Brazil	Cross-sectional	43	—	—	28.8 months (17)	PCR	21
[23]-India	Cross-sectional	76	—	—	36 months a	PCR	NR
[11]-Korea	Cross-sectional	54	—	—	22 months	In situ hybridization in formalin-fixed paraffin-embedded retinoblastoma tissues	NR
[24]-Thailand	Cross-sectional	111	12	Coats disease, endophthalmitis, and congenital glaucoma	NR	PCR	56
[26]-Iran	Cross-sectional	61	v	—	28.6 years (17.3)	PCR	32
[12]-Multicenter in North America	Cross-sectional	40	—	—	NR	PCR	23

NR, not reported; RB, retinoblastoma; PRC, polymerase chain reaction.

^a Range.

^b Range.