Correlation between RPPA expression and clinical features
Overview
Introduction

This pipeline uses various statistical tests to identify RPPAs whose expression levels correlated to selected clinical features.

Summary

Testing the association between 217 genes and 9 clinical features across 658 samples, statistically thresholded by P value < 0.05 and Q value < 0.3, 8 clinical features related to at least one genes.

  • 30 genes correlated to 'DAYS_TO_DEATH_OR_LAST_FUP'.

    • IGFBP2|IGFBP2 ,  SERPINE1|PAI-1 ,  SCD1|SCD1 ,  EGFR|EGFR_PY1173 ,  WWTR1|TAZ ,  ...

  • 30 genes correlated to 'YEARS_TO_BIRTH'.

    • ASNS|ASNS ,  IGFBP2|IGFBP2 ,  ANXA1|ANNEXIN-1 ,  PARK7|DJ-1 ,  PEA15|PEA15 ,  ...

  • 30 genes correlated to 'TUMOR_TISSUE_SITE'.

    • PGR|PR ,  BAD|BAD_PS112 ,  RPS6KA1|P90RSK ,  ACVRL1|ACVRL1 ,  TIGAR|TIGAR ,  ...

  • 29 genes correlated to 'GENDER'.

    • SHC1|SHC_PY317 ,  GSK3A GSK3B|GSK3-ALPHA-BETA ,  TSC2|TUBERIN ,  TSC1|TSC1 ,  BRAF|B-RAF ,  ...

  • 30 genes correlated to 'RADIATION_THERAPY'.

    • RPS6KA1|P90RSK ,  ERBB3|HER3_PY1289 ,  PRKCD|PKC-DELTA_PS664 ,  EIF4E|EIF4E ,  SCD1|SCD1 ,  ...

  • 5 genes correlated to 'KARNOFSKY_PERFORMANCE_SCORE'.

    • ASNS|ASNS ,  IGFBP2|IGFBP2 ,  COPS5|JAB1 ,  CTNNA1|ALPHA-CATENIN ,  SCD1|SCD1

  • 30 genes correlated to 'HISTOLOGICAL_TYPE'.

    • SYK|SYK ,  BAD|BAD_PS112 ,  AR|AR ,  TIGAR|TIGAR ,  PGR|PR ,  ...

  • 7 genes correlated to 'ETHNICITY'.

    • SRC|SRC_PY527 ,  GSK3A GSK3B|GSK3_PS9 ,  EIF4EBP1|4E-BP1_PT37_T46 ,  GSK3A GSK3B|GSK3-ALPHA-BETA_PS21_S9 ,  AKT1S1|PRAS40_PT246 ,  ...

  • No genes correlated to 'RACE'

Results
Overview of the results

Complete statistical result table is provided in Supplement Table 1

Table 1.  Get Full Table This table shows the clinical features, statistical methods used, and the number of genes that are significantly associated with each clinical feature at P value < 0.05 and Q value < 0.3.

Clinical feature Statistical test Significant genes Associated with                 Associated with
DAYS_TO_DEATH_OR_LAST_FUP Cox regression test N=30 shorter survival N=22 longer survival N=8
YEARS_TO_BIRTH Spearman correlation test N=30 older N=18 younger N=12
TUMOR_TISSUE_SITE Wilcoxon test N=30 central nervous system N=30 brain N=0
GENDER Wilcoxon test N=29 male N=29 female N=0
RADIATION_THERAPY Wilcoxon test N=30 yes N=30 no N=0
KARNOFSKY_PERFORMANCE_SCORE Spearman correlation test N=5 higher score N=3 lower score N=2
HISTOLOGICAL_TYPE Kruskal-Wallis test N=30        
RACE Kruskal-Wallis test   N=0        
ETHNICITY Wilcoxon test N=7 not hispanic or latino N=7 hispanic or latino N=0
Clinical variable #1: 'DAYS_TO_DEATH_OR_LAST_FUP'

30 genes related to 'DAYS_TO_DEATH_OR_LAST_FUP'.

Table S1.  Basic characteristics of clinical feature: 'DAYS_TO_DEATH_OR_LAST_FUP'

DAYS_TO_DEATH_OR_LAST_FUP Duration (Months) 0-211.2 (median=16.5)
  censored N = 393
  death N = 264
     
  Significant markers N = 30
  associated with shorter survival 22
  associated with longer survival 8
List of top 10 genes differentially expressed by 'DAYS_TO_DEATH_OR_LAST_FUP'

Table S2.  Get Full Table List of top 10 genes significantly associated with 'Time to Death' by Cox regression test

HazardRatio Wald_P Q C_index
IGFBP2|IGFBP2 1.77 5.831e-13 1.3e-10 0.63
SERPINE1|PAI-1 1.57 2.508e-12 2.7e-10 0.578
SCD1|SCD1 0.04 6.246e-09 4.5e-07 0.269
EGFR|EGFR_PY1173 1.36 3.522e-08 1.9e-06 0.483
WWTR1|TAZ 2.2 3.996e-07 1.5e-05 0.54
ERRFI1|MIG-6 3.7 4.28e-07 1.5e-05 0.533
YAP1|YAP 2.1 2.972e-06 9.2e-05 0.533
ERBB2|HER2_PY1248 1.36 7.349e-06 2e-04 0.498
EGFR|EGFR_PY1068 1.2 2.467e-05 0.00058 0.477
YWHAE|14-3-3_EPSILON 0.3 2.67e-05 0.00058 0.408
Clinical variable #2: 'YEARS_TO_BIRTH'

30 genes related to 'YEARS_TO_BIRTH'.

Table S3.  Basic characteristics of clinical feature: 'YEARS_TO_BIRTH'

YEARS_TO_BIRTH Mean (SD) 48.56 (16)
  Significant markers N = 30
  pos. correlated 18
  neg. correlated 12
List of top 10 genes differentially expressed by 'YEARS_TO_BIRTH'

Table S4.  Get Full Table List of top 10 genes significantly correlated to 'YEARS_TO_BIRTH' by Spearman correlation test

SpearmanCorr corrP Q
ASNS|ASNS 0.2592 1.517e-11 3.29e-09
IGFBP2|IGFBP2 0.238 6.524e-10 7.08e-08
ANXA1|ANNEXIN-1 0.2041 5.492e-06 0.000397
PARK7|DJ-1 -0.1731 8.083e-06 0.000435
PEA15|PEA15 -0.1714 1.001e-05 0.000435
SRC|SRC_PY527 -0.1626 2.824e-05 0.00093
PDCD4|PDCD4 -0.1621 3e-05 0.00093
SERPINE1|PAI-1 0.1494 0.0001213 0.00329
CAV1|CAVEOLIN-1 0.139 0.000351 0.00846
FN1|FIBRONECTIN 0.1379 0.0003935 0.00854
Clinical variable #3: 'TUMOR_TISSUE_SITE'

30 genes related to 'TUMOR_TISSUE_SITE'.

Table S5.  Basic characteristics of clinical feature: 'TUMOR_TISSUE_SITE'

TUMOR_TISSUE_SITE Labels N
  BRAIN 230
  CENTRAL NERVOUS SYSTEM 428
     
  Significant markers N = 30
  Higher in CENTRAL NERVOUS SYSTEM 30
  Higher in BRAIN 0
List of top 10 genes differentially expressed by 'TUMOR_TISSUE_SITE'

Table S6.  Get Full Table List of top 10 genes differentially expressed by 'TUMOR_TISSUE_SITE'

W(pos if higher in 'CENTRAL NERVOUS SYSTEM') wilcoxontestP Q AUC
PGR|PR 35828 8.432e-09 1.83e-06 0.636
BAD|BAD_PS112 62133 2.799e-08 3.04e-06 0.6312
RPS6KA1|P90RSK 61257 2.257e-07 1.48e-05 0.6223
ACVRL1|ACVRL1 37264.5 2.722e-07 1.48e-05 0.6214
TIGAR|TIGAR 59550 8.886e-06 0.000386 0.6049
CDH1|E-CADHERIN 39091 1.323e-05 0.000479 0.6029
RAB11A RAB11B|RAB11 58647 5.029e-05 0.00156 0.5958
ESR1|ER-ALPHA_PS118 40364 0.0001397 0.00379 0.59
SMAD1|SMAD1 57739 0.0002486 0.00599 0.5865
TGM2|TRANSGLUTAMINASE 41080.5 0.0004643 0.0101 0.5827
Clinical variable #4: 'GENDER'

29 genes related to 'GENDER'.

Table S7.  Basic characteristics of clinical feature: 'GENDER'

GENDER Labels N
  FEMALE 282
  MALE 376
     
  Significant markers N = 29
  Higher in MALE 29
  Higher in FEMALE 0
List of top 10 genes differentially expressed by 'GENDER'

Table S8.  Get Full Table List of top 10 genes differentially expressed by 'GENDER'. 1 significant gene(s) located in sex chromosomes is(are) filtered out.

W(pos if higher in 'MALE') wilcoxontestP Q AUC
SHC1|SHC_PY317 66534 2.122e-08 4.6e-06 0.6275
GSK3A GSK3B|GSK3-ALPHA-BETA 42676 1.829e-05 0.00198 0.5975
TSC2|TUBERIN 43104 4.001e-05 0.00253 0.5935
TSC1|TSC1 43189 4.657e-05 0.00253 0.5927
BRAF|B-RAF 43392 6.661e-05 0.00289 0.5908
PRKAA1|AMPK_ALPHA 43699 0.000113 0.00409 0.5879
RAF1|C-RAF 43858.5 0.0001478 0.00458 0.5864
STAT5A|STAT5-ALPHA 43983 0.0001817 0.00493 0.5852
AKT1 AKT2 AKT3|AKT 44433 0.0003756 0.00906 0.5809
RBM15|RBM15 45034 0.000941 0.0199 0.5753
Clinical variable #5: 'RADIATION_THERAPY'

30 genes related to 'RADIATION_THERAPY'.

Table S9.  Basic characteristics of clinical feature: 'RADIATION_THERAPY'

RADIATION_THERAPY Labels N
  NO 181
  YES 428
     
  Significant markers N = 30
  Higher in YES 30
  Higher in NO 0
List of top 10 genes differentially expressed by 'RADIATION_THERAPY'

Table S10.  Get Full Table List of top 10 genes differentially expressed by 'RADIATION_THERAPY'

W(pos if higher in 'YES') wilcoxontestP Q AUC
RPS6KA1|P90RSK 30380.5 2.562e-05 0.00556 0.6078
ERBB3|HER3_PY1289 31991.5 0.0006802 0.0738 0.587
PRKCD|PKC-DELTA_PS664 32531 0.001775 0.1 0.5801
EIF4E|EIF4E 44872.5 0.001981 0.1 0.5792
SCD1|SCD1 15096 0.002745 0.1 0.5896
PRKCB|PKC-PAN_BETAII_PS660 32817 0.002869 0.1 0.5764
XRCC1|XRCC1 44487 0.003746 0.1 0.5743
BAX|BAX 44454 0.003949 0.1 0.5738
CCNE1|CYCLIN_E1 44317 0.004906 0.1 0.5721
PRKCA |PKC-ALPHA_PS657 33170 0.005054 0.1 0.5718
Clinical variable #6: 'KARNOFSKY_PERFORMANCE_SCORE'

5 genes related to 'KARNOFSKY_PERFORMANCE_SCORE'.

Table S11.  Basic characteristics of clinical feature: 'KARNOFSKY_PERFORMANCE_SCORE'

KARNOFSKY_PERFORMANCE_SCORE Mean (SD) 81.35 (15)
  Significant markers N = 5
  pos. correlated 3
  neg. correlated 2
List of 5 genes differentially expressed by 'KARNOFSKY_PERFORMANCE_SCORE'

Table S12.  Get Full Table List of 5 genes significantly correlated to 'KARNOFSKY_PERFORMANCE_SCORE' by Spearman correlation test

SpearmanCorr corrP Q
ASNS|ASNS -0.2122 1.306e-05 0.00283
IGFBP2|IGFBP2 -0.1559 0.001438 0.156
COPS5|JAB1 0.271 0.002994 0.169
CTNNA1|ALPHA-CATENIN 0.1885 0.003118 0.169
SCD1|SCD1 0.1841 0.004287 0.186
Clinical variable #7: 'HISTOLOGICAL_TYPE'

30 genes related to 'HISTOLOGICAL_TYPE'.

Table S13.  Basic characteristics of clinical feature: 'HISTOLOGICAL_TYPE'

HISTOLOGICAL_TYPE Labels N
  ASTROCYTOMA 147
  GLIOBLASTOMA MULTIFORME (GBM) 17
  OLIGOASTROCYTOMA 114
  OLIGODENDROGLIOMA 167
  TREATED PRIMARY GBM 3
  UNTREATED PRIMARY (DE NOVO) GBM 210
     
  Significant markers N = 30
List of top 10 genes differentially expressed by 'HISTOLOGICAL_TYPE'

Table S14.  Get Full Table List of top 10 genes differentially expressed by 'HISTOLOGICAL_TYPE'

kruskal_wallis_P Q
SYK|SYK 5.316e-17 1.15e-14
BAD|BAD_PS112 4.862e-10 5.28e-08
AR|AR 1.254e-08 6.67e-07
TIGAR|TIGAR 1.531e-08 6.67e-07
PGR|PR 1.536e-08 6.67e-07
BAX|BAX 9.305e-08 3.37e-06
ANXA1|ANNEXIN-1 1.415e-07 4.39e-06
PRDX1|PRDX1 2.949e-07 8e-06
MAPK14|P38_MAPK 5.422e-07 1.31e-05
ERBB3|HER3_PY1289 6.299e-07 1.32e-05
Clinical variable #8: 'RACE'

No gene related to 'RACE'.

Table S15.  Basic characteristics of clinical feature: 'RACE'

RACE Labels N
  AMERICAN INDIAN OR ALASKA NATIVE 1
  ASIAN 12
  BLACK OR AFRICAN AMERICAN 45
  WHITE 576
     
  Significant markers N = 0
Clinical variable #9: 'ETHNICITY'

7 genes related to 'ETHNICITY'.

Table S16.  Basic characteristics of clinical feature: 'ETHNICITY'

ETHNICITY Labels N
  HISPANIC OR LATINO 29
  NOT HISPANIC OR LATINO 571
     
  Significant markers N = 7
  Higher in NOT HISPANIC OR LATINO 7
  Higher in HISPANIC OR LATINO 0
List of 7 genes differentially expressed by 'ETHNICITY'

Methods & Data
Input
  • Expresson data file = GBMLGG-TP.rppa.txt

  • Clinical data file = GBMLGG-TP.merged_data.txt

  • Number of patients = 658

  • Number of genes = 217

  • Number of clinical features = 9

Selected clinical features
  • Further details on clinical features selected for this analysis, please find a documentation on selected CDEs (Clinical Data Elements). The first column of the file is a formula to convert values and the second column is a clinical parameter name.

  • Survival time data

    • Survival time data is a combined value of days_to_death and days_to_last_followup. For each patient, it creates a combined value 'days_to_death_or_last_fup' using conversion process below.

      • if 'vital_status'==1(dead), 'days_to_last_followup' is always NA. Thus, uses 'days_to_death' value for 'days_to_death_or_fup'

      • if 'vital_status'==0(alive),

        • if 'days_to_death'==NA & 'days_to_last_followup'!=NA, uses 'days_to_last_followup' value for 'days_to_death_or_fup'

        • if 'days_to_death'!=NA, excludes this case in survival analysis and report the case.

      • if 'vital_status'==NA,excludes this case in survival analysis and report the case.

    • cf. In certain diesase types such as SKCM, days_to_death parameter is replaced with time_from_specimen_dx or time_from_specimen_procurement_to_death .

  • This analysis excluded clinical variables that has only NA values.

Survival analysis

For survival clinical features, Wald's test in univariate Cox regression analysis with proportional hazards model (Andersen and Gill 1982) was used to estimate the P values using the 'coxph' function in R. Kaplan-Meier survival curves were plot using the four quartile subgroups of patients based on expression levels

Correlation analysis

For continuous numerical clinical features, Spearman's rank correlation coefficients (Spearman 1904) and two-tailed P values were estimated using 'cor.test' function in R

Wilcoxon rank sum test (Mann-Whitney U test)

For two groups (mutant or wild-type) of continuous type of clinical data, wilcoxon rank sum test (Mann and Whitney, 1947) was applied to compare their mean difference using 'wilcox.test(continuous.clinical ~ as.factor(group), exact=FALSE)' function in R. This test is equivalent to the Mann-Whitney test.

Q value calculation

For multiple hypothesis correction, Q value is the False Discovery Rate (FDR) analogue of the P value (Benjamini and Hochberg 1995), defined as the minimum FDR at which the test may be called significant. We used the 'Benjamini and Hochberg' method of 'p.adjust' function in R to convert P values into Q values.

References
[1] Andersen and Gill, Cox's regression model for counting processes, a large sample study, Annals of Statistics 10(4):1100-1120 (1982)
[2] Spearman, C, The proof and measurement of association between two things, Amer. J. Psychol 15:72-101 (1904)
[3] Mann and Whitney, On a Test of Whether one of Two Random Variables is Stochastically Larger than the Other, Annals of Mathematical Statistics 18 (1), 50-60 (1947)
[4] Benjamini and Hochberg, Controlling the false discovery rate: a practical and powerful approach to multiple testing, Journal of the Royal Statistical Society Series B 59:289-300 (1995)