Table 5.

Characteristics of the included datasets in meta-analysis

Study	Population	Accession number	16S region	Sequencing platform	CCN	Cases	Controls	Age (y/o)
Study 1 Apopa et al. [23]	AF & EU	PRJNA472758	27 F & 519R	Illumina MiSeq	14	9	5	50–80
Study 2 Nejman et al. [47]	IL	PRJNA624822	*	*	476	245	231	NA
Study 3 Yu et al. [24]	IT 1	PRJNA303190	V3–V4	Illumina MiSeq	257	50	207	40–80
Study 4 -	IT 2	PRJNA327258	NA	Illumina MiSeq	53	27	26	40–80
Study 5 Kovaleva et al. [48]	RU	PRJNA647170	V3–V4	Illumina MiSeq	49	25	24	62$\pm 10$
Total					849	356	493

CCN: Case-Control Number; Cases: either AC (lung adenocarcinoma) or SCC (lung squamous cell carcinoma); Controls: tumor-adjacent normal tissues; y/o: years old; AF & EU: Africa & Europe; IL: Israel; IT: Italy; RU: Russia; NA: Not Available; * Five regions of the 16S rRNA gene were amplified and sequenced on Illumina HiSeq, MiSeq or NextSeq