REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Anti-PCDHB4	ThermoFisher Scientific	Cat# PA5-120577; RRID: AB_2914149
Anti-β-actin antibody	TransGen Biotech	Cat# HC201; RRID: AB_2860007
Bacterial and virus strains
DH5α	TOLOBIO	Cat# CC96102-02
pClone007 Simple Vector	TsingKe Biotech	Cat# TSV-007S
Biological samples
FFPE samples of human SCLC and adjacent non-tumor tissues	The First Affiliated Hospital of USTC (Hefei, China)	N/A
Blood samples of SCLC patients	The First Affiliated Hospital of USTC (Hefei, China)	N/A
Chemicals, peptides, and recombinant proteins
RPMI-1640	Gibco	Cat# 11875500BT
Fetal bovine serum	ExCell Bio	Cat# FSP500
Penicillin-streptomycin solution	Hyclone	Cat# SV30010
Cisplatin	MCE	Cat# HY-17394
Critical commercial assays
GeneRead DNA FFPE Kit	Qiagen	Cat# 180134
Circulating Nucleic Acids Kit	Qiagen	Cat# 55114
DNA Methylation kit	Zymo Research	Cat# D5001
RNA extraction kit	Tiangen	Cat# DP451
Reverse transcription kit	TransGen	Cat# AT301-03
BCA Protein Assay Kit	Beyotime	Cat# P0009
NEBNext Multiplex Oligos for Illumina	New England BioLabs	Cat# E7335L
KAPA HiFi Hotstart ReadyMix	KAPA Biosystems	Cat# KK2602
KAPA HyperPrep Kit	KAPA Biosystems	Cat# KK8504
MagMeDIP Kit	Diagenode	Cat# C02010021
HighGene transfection reagent	ABclonal Technology	Cat# RM09014
CellTiter-Glo Luminescent Cell Viability assay	Promega	Cat# G7572
Deposited data
Gene expression data and clinical information of SCLC	George et al.12	https://doi.org/10.1038/nature14664
GEO: GSE60052	Gene Expression Omnibus (GEO) database	https://www.ncbi.nlm.nih.gov/geo/
GEO: GSE40275	Gene Expression Omnibus (GEO) database	https://www.ncbi.nlm.nih.gov/geo/
GEO: GSE138474	Gene Expression Omnibus (GEO) database	https://www.ncbi.nlm.nih.gov/geo/
SCLC scRNA-seq dataset	Tian et al.13	https://doi.org/10.1038/s41392-022-01150-4
Gene expression data and clinical information of LUSC	TCGA	https://xenabrowser.net/datapages/
Genomics of Drug Sensitivity in Cancer (GDSC) database	GDSC	https://www.cancerrxgene.org/
MeDIP-seq data of SCLC	This study	GSA-Human: HRA007706
Experimental models: cell lines
BEAS-2B	Anhui Medical University	N/A
H69	ATCC	Cat# HTB-119
H82	ATCC	Cat# HTB-175
H446	Chinese Academy of Sciences	N/A
H526	ATCC	Cat# CRL-5811
SBC-2	HyCyte	Cat# TCH-C432
Oligonucleotides
See Table S4 for primer sequence used in this study	This study	N/A
Recombinant DNA
pCMV-3Tag	Agilent Technologies	Cat# 240195
pCMV-3Tag-PCDHB4	This study	N/A
Software and algorithms
R	The R Project for Statistical Computing	www.r-project.org/
Survival	R CRAN	https://cran.r-project.org/web/packages/survival/index.html
survminer	R CRAN	https://cran.r-project.org/web/packages/survminer/index.html
limma	Bioconductor	https://bioconductor.org/packages/release/bioc/html/limma.html
ChAMP	Bioconductor	https://bioconductor.org/packages/release/bioc/html/ChAMP.html
clusterProfiler	Bioconductor	https://www.bioconductor.org/packages/release/bioc/html/clusterProfiler.html
Seurat	satijalab	https://satijalab.org/seurat/
GSVA	R package	https://github.com/rcastelo/GSVA
TIMER2.0	X Shirley Liu Lab 2020 | Dana Farber Cancer Institute	http://timer.cistrome.org/
Macs2	Github	https://github.com/taoliu/MACS
deeptools	Github	https://github.com/deeptools/deepTools/
Integrative Genomics Viewer (IGV)	Broad Institute	https://software.broadinstitute.org/software/igv/
GraphPad Prism 9	GraphPad Software	https://www.graphpad.com/
ImageJ	ImageJ Software	https://imagej.nih.gov/ij