Replication of results: Defining T Cell States Associated with Response to Checkpoint Immunotherapy in Melanoma
Method: 'Differential expression analysis' part
Data: 'GSE120575_Sade_Feldman_melanoma_single_cells_TPM_GEO.txt', Gene expression values of 6,350 CD8+ T cells (cell ID's found in Table S2)
Truth: Table S2
Results:
- Applied Fisher's Exact test for corresponding table, respose & Non-response (results can be found in '/Results/pvalueSort.csv')
- Applied Fisher's Exact test for corresponding table, CD8_B & CD8_G (code can be found in 'Identify_markers.rmd')
head(pvalueSort)
p_value | mean_exp_in_R | mean_exp_in_NR | per_in_R | per_in_NR | log2_R_NR_ |
---|---|---|---|---|---|
CD38 | 1.968650e-112 | 1.1909712 | 3.4240014 | 0.15226940 | 0.42710997 |
PRF1 | 7.866785e-96 | 4.4266911 | 7.0580353 | 0.50561249 | 0.76889096 |
NKG7 | 3.618114e-91 | 7.7752074 | 10.4359219 | 0.70815032 | 0.91141595 |
IFI6 | 4.182860e-71 | 2.3380918 | 4.3357429 | 0.33723768 | 0.57498256 |
PSME2 | 2.122274e-70 | 4.2568619 | 6.5887143 | 0.46412884 | 0.69681469 |
Method: 'Survival analysis' part
Data: Table S3, including patients' survival data, patients status and immunofluorescence-generated TCF7+CD8+/TCF7−CD8+ ratios.
Truth: Figure. 3H
Results: Kaplan-Meier survival curve for 33 patients treated with anti-PD-1 therapy. Patients were divided into two groups based on TCF7+CD8+/TCF7−CD8+ ratio (n = 16 > 1; n = 17 < 1) from IF.
Method: 'Unsupervised clustering of immune cells' parts
Data: Using all genes with variance > 6, yielding ∼4000 genes. /Results/clusterData.csv
Truth: Table S1, S2, S4
Results: Determine the optimal number of clusters
- Step 1 Applied the elbow method
Examined how much of the complexity each cluster captures by applying the elbow method Select the solutions that are near plateau (k = 10,..., 15)
- Step 2 Performed differentical expression
Performed differentical expression anlysis to search for gene markers that are siginificatly more highly expressed in a specific cluster as compared to all other clusters (excluded solutions with clusters that have too few marker genes (< 20) distinguishing between them and the rest of the cells.)
- Step 3 Robustness analysis
Finally, we performed a robustness analysis and selected the clustering solution with the highest median robustness score.
Method: 'Unsupervised clustering of T cells' parts, same as above
Data: Gene expression values of 6,350 CD8+ T cells (cell ID's found in Table S2)