Correlation between copy number variations of arm-level result and selected clinical features
Lymphoid Neoplasm Diffuse Large B-cell Lymphoma (Primary solid tumor)
16 April 2014  |  analyses__2014_04_16
Maintainer Information
Citation Information
Maintained by TCGA GDAC Team (Broad Institute/MD Anderson Cancer Center/Harvard Medical School)
Cite as Broad Institute TCGA Genome Data Analysis Center (2014): Correlation between copy number variations of arm-level result and selected clinical features. Broad Institute of MIT and Harvard. doi:10.7908/C1V69H66
Overview
Introduction

This pipeline computes the correlation between significant arm-level copy number variations (cnvs) and selected clinical features.

Summary

Testing the association between copy number variation 17 arm-level events and 3 clinical features across 21 patients, one significant finding detected with Q value < 0.25.

  • xq loss cnv correlated to 'Time to Death'.

Results
Overview of the results

Table 1.  Get Full Table Overview of the association between significant copy number variation of 17 arm-level events and 3 clinical features. Shown in the table are P values (Q values). Thresholded by Q value < 0.25, one significant finding detected.

Clinical
Features
Time
to
Death
AGE GENDER
nCNV (%) nWild-Type logrank test t-test Fisher's exact test
xq loss 3 (14%) 18 0.00468
(0.239)
0.91
(1.00)
0.257
(1.00)
1q gain 4 (19%) 17 0.405
(1.00)
0.42
(1.00)
0.618
(1.00)
3p gain 3 (14%) 18 0.418
(1.00)
0.264
(1.00)
1
(1.00)
3q gain 4 (19%) 17 0.418
(1.00)
0.993
(1.00)
1
(1.00)
7p gain 7 (33%) 14 0.317
(1.00)
0.905
(1.00)
1
(1.00)
7q gain 6 (29%) 15 0.522
(1.00)
0.717
(1.00)
1
(1.00)
11p gain 3 (14%) 18 0.569
(1.00)
0.407
(1.00)
0.257
(1.00)
11q gain 7 (33%) 14 0.249
(1.00)
0.273
(1.00)
0.656
(1.00)
12p gain 3 (14%) 18 0.724
(1.00)
0.0499
(1.00)
1
(1.00)
12q gain 3 (14%) 18 0.724
(1.00)
0.0499
(1.00)
1
(1.00)
16p gain 3 (14%) 18 0.808
(1.00)
0.844
(1.00)
1
(1.00)
16q gain 3 (14%) 18 0.316
(1.00)
0.606
(1.00)
0.531
(1.00)
18p gain 4 (19%) 17 0.389
(1.00)
0.0811
(1.00)
1
(1.00)
18q gain 4 (19%) 17 0.389
(1.00)
0.0811
(1.00)
1
(1.00)
21q gain 5 (24%) 16 0.892
(1.00)
0.718
(1.00)
1
(1.00)
15q loss 4 (19%) 17 0.522
(1.00)
0.964
(1.00)
1
(1.00)
16q loss 3 (14%) 18 0.724
(1.00)
0.91
(1.00)
0.257
(1.00)
'xq loss' versus 'Time to Death'

P value = 0.00468 (logrank test), Q value = 0.24

Table S1.  Gene #17: 'xq loss' versus Clinical Feature #1: 'Time to Death'

nPatients nDeath Duration Range (Median), Month
ALL 21 4 2.0 - 211.2 (31.7)
XQ LOSS MUTATED 3 1 4.1 - 31.7 (19.6)
XQ LOSS WILD-TYPE 18 3 2.0 - 211.2 (38.3)

Figure S1.  Get High-res Image Gene #17: 'xq loss' versus Clinical Feature #1: 'Time to Death'

Methods & Data
Input
  • Copy number data file = transformed.cor.cli.txt

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

  • Number of patients = 21

  • Number of significantly arm-level cnvs = 17

  • Number of selected clinical features = 3

  • Exclude regions that fewer than K tumors have mutations, K = 3

Survival analysis

For survival clinical features, the Kaplan-Meier survival curves of tumors with and without gene mutations were plotted and the statistical significance P values were estimated by logrank test (Bland and Altman 2004) using the 'survdiff' function in R

Student's t-test analysis

For continuous numerical clinical features, two-tailed Student's t test with unequal variance (Lehmann and Romano 2005) was applied to compare the clinical values between tumors with and without gene mutations using 't.test' function in R

Fisher's exact test

For binary or multi-class clinical features (nominal or ordinal), two-tailed Fisher's exact tests (Fisher 1922) were used to estimate the P values using the 'fisher.test' function in R

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.

Download Results

In addition to the links below, the full results of the analysis summarized in this report can also be downloaded programmatically using firehose_get, or interactively from either the Broad GDAC website or TCGA Data Coordination Center Portal.

References
[1] Bland and Altman, Statistics notes: The logrank test, BMJ 328(7447):1073 (2004)
[2] Lehmann and Romano, Testing Statistical Hypotheses (3E ed.), New York: Springer. ISBN 0387988645 (2005)
[3] Fisher, R.A., On the interpretation of chi-square from contingency tables, and the calculation of P, Journal of the Royal Statistical Society 85(1):87-94 (1922)
[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)