The primary objective was to investigate the epidemiology, molecular characteristics, and clinical survival to identify potential transcriptome biomarkers to promote early diagnosis and screening of triple-negative breast cancer patients. Early-stage triple-negative breast cancer patients (E-TNBC) and late-stage triple-negative breast cancer patients (L-TNBC) were identified from the Surveillance, Epidemiology, and End Results database from 2010 to 2019. The difference in cancer specific survival (CSS) and overall survival (OS) between E-TNBC and L-TNBC was analyzed via a Kaplan–Meier plotter. 118 triple-negative breast cancer samples and 114 normal samples with the RNA sequencing expression data were selected from the cohort of TCGA breast cancer from UCSC Xena Database. The study involved 13,690 patients with L-TNBC and 44,994 patients with E-TNBC. L-TNBC patients were more frequently to be ≤ 60 years old (54.9% vs 52.2%), multiple primary site (44.0% vs 30.1%), and were more likely to receive radiotherapy (49.6% vs 47.4%) and chemotherapy (81.1% vs 72.1%), while L-TNBC patients were less likely to be white (68.7% vs 73.0%), married or with domestic partner (46.7% vs 54.7%), poorly differentiated grade (54.0% vs 61.9%), < 3 months from diagnosis to treatment (91.6% vs 96.4%), and were less likely to receive surgery (72.3% vs 95.4%). Stage-stratified survival analysis revealed that the prognosis of L-TNBC was worse when compared to E-TNBC, Kaplan–Meier analysis demonstrated that there were striking differences in OS and CSS between E-TNBC and L-TNBC. In the multivariable regression models, L-TNBC was the single highest risk factor, with a death risk that was 4.741 and 6.074 times higher than E-TNBC in terms of OS and CSS, respectively. The results also showed that treatment with surgery, radiation, or chemotherapy was effective for a better prognosis. Transcriptome analyses revealed that the top 5 upregulated genes in L-TNBC were, respectively, ISX, ALOX15B, MADCAM1, TP63, and ARG1 compared with E-TNBC. And the top 5 downregulated genes were, respectively, CTAG1B, CT45A1, MAGEC2, TFF2, and TNFRSF11B. The L-TNBC exhibited a lower rate of survival than E-TNBC, and the 2 groups differed in terms of transcriptome characteristics. To date, the diagnostic value of T cell-mediated tumor killing portraits on E-TNBC may not be completely recognized.