CPXM2 and small cell carcinoma: Through this analysis, we successfully identified specific proteins associated with different lung cancer subtypes: AGRN, CD5L, GNPDA, ITGB2, SEPTIN3 with adenocarcinoma; ACAN, C7, DMP1, DPP10, GP1BA, HEPH with squamous cell carcinoma; and ACADSB, CEACAM6, COX6B1, CPXM2, IL12RB2 with small cell carcinoma.