Mutation Analysis (MutSig 2CV v3.1)
Uterine Corpus Endometrioid Carcinoma (Serous)
04 October 2018  |  None
Maintainer Information
Maintained by David Heiman (Broad Institute)
Overview
Introduction

This report serves to describe the mutational landscape and properties of a given cohort, as well as rank genes and genesets according to mutational significance. MutSig 2CV v3.1 was used to generate the results found in this report.

  • Working with cohort: CPTAC3-UCEC-Serous

  • Number of patients in cohort: 16

Input

The input for this pipeline is an annotated .maf file describing the mutations called for each individual in the given cancer cohort, and their properties.

Summary
Results
Breakdown of Mutation Rates by Category Type

Table 1.  Get Full Table A breakdown of mutation rates per category discovered for this cohort.

left from change right n N rate ci_low ci_high relrate autoname name type
ACGT C t G 296 75860266 3.9e-06 3.5e-06 4.4e-06 14 ACGT[C->t]G *CpG->T point
ACGT C fs G 66 151720532 4.4e-07 3.4e-07 5.5e-07 1.6 ACGT[C->fs]G *CpG->(G/A) point
ACGT C ts ACT 464 1253418736 3.7e-07 3.4e-07 4.1e-07 1.3 ACGT[C->ts]ACT *Cp(A/C/T)->(A/T) point
ACGT C f ACT 95 626709368 1.5e-07 1.2e-07 1.9e-07 0.55 ACGT[C->f]ACT *Cp(A/C/T)->G point
ACGT A tfs ACGT 231 2036387739 1.1e-07 9.9e-08 1.3e-07 0.41 ACGT[A->tfs]ACGT A->mut point
Lego Plots

The mutation spectrum is depicted in the lego plots below in which the 96 possible mutation types are subdivided into six large blocks, color-coded to reflect the base substitution type. Each large block is further subdivided into the 16 possible pairs of 5' and 3' neighbors, as listed in the 4x4 trinucleotide context legend. The height of each block corresponds to the mutation frequency for that kind of mutation (counts of mutations normalized by the base coverage in a given bin). The shape of the spectrum is a signature for dominant mutational mechanisms in different tumor types.

Figure 1.  Get High-res Image SNV Mutation rate lego plot for entire cohort. Each bin is normalized by base coverage for that bin. Colors represent the six SNV types on the upper right. The three-base context for each mutation is labeled in the 4x4 legend on the lower right. The fractional breakdown of SNV counts is shown in the pie chart on the upper left. If this figure is blank, not enough information was provided in the MAF to generate it.

Figure 2.  Get High-res Image SNV Mutation rate lego plots for 4 slices of mutation allele fraction (0<=AF<0.1, 0.1<=AF<0.25, 0.25<=AF<0.5, & 0.5<=AF) . The color code and three-base context legends are the same as the previous figure. If this figure is blank, not enough information was provided in the MAF to generate it.

CoMut Plot

Figure 3.  Get High-res Image The matrix in the center of the figure represents individual mutations in patient samples, color-coded by type of mutation, for the significantly mutated genes. The rate of synonymous and non-synonymous mutations is displayed at the top of the matrix. The barplot on the left of the matrix shows the number of mutations in each gene. The percentages represent the fraction of tumors with at least one mutation in the specified gene. The barplot to the right of the matrix displays the q-values for the most significantly mutated genes. The purple boxplots below the matrix (only displayed if required columns are present in the provided MAF) represent the distributions of allelic fractions observed in each sample. The plot at the bottom represents the base substitution distribution of individual samples, using the same categories that were used to calculate significance.

Significantly Mutated Genes

Column Descriptions:

  • codelen = the gene's coding length

  • nncd = number of noncoding mutations in this gene across the cohort

  • nsil = number of silent mutations in this gene across the cohort

  • nmis = number of missense mutations in this gene across the cohort

  • nstp = number of readthrough mutations in this gene across the cohort

  • nspl = number of splice site mutations in this gene across the cohort

  • nind = number of indels in this gene across the cohort

  • nnon = number of (nonsilent) mutations in this gene across the cohort

  • npat = number of patients (individuals) with at least one nonsilent mutation

  • nsite = number of unique sites having a non-silent mutation

  • Abundance (pCV) = Probability that the gene's overall nonsilent mutation rate exceeds its inferred background mutation rate (BMR), which is computed based on the gene's own silent mutation rate plus silent mutation rates of genes with similar covariates. BMR calculations are normalized with respect to patient-specific and sequence context-specific mutation rates.

  • Clustering (pCL) = Probability that recurrently mutated loci in this gene have more mutations than expected by chance. While pCV assesses the gene's overall mutation burden, pCL assesses the burden of specific sites within the gene. This allows MutSig to differentiate between genes with uniformly distributed mutations and genes with localized hotspots.

  • Conservation (pFN) = Probability that mutations within this gene occur disproportionately at evolutionarily conserved sites. Sites highly conserved across vertebrates are assumed to have greater functional impact than weakly conserved sites.

  • p = p-value (overall)

  • q = q-value, False Discovery Rate (Benjamini-Hochberg procedure)

Table 2.  Get Full Table A Ranked List of Significantly Mutated Genes. Number of significant genes found: 7. Number of genes displayed: 35. Click on a gene name to display its stick figure depicting the distribution of mutations and mutation types across the chosen gene (this feature may not be available for all significant genes).

rank gene longname codelen nnei nncd nsil nmis nstp nspl nind nnon npat nsite pCV pCL pFN p q
1 TP53 tumor protein p53 1314 498 0 0 9 1 1 1 12 11 12 5.8e-16 1 0.016 1.3e-15 2.4e-11
2 PTEN phosphatase and tensin homolog (mutated in multiple advanced cancers 1) 1244 1000 0 0 2 1 0 2 5 5 4 6.6e-09 0.063 0.25 4e-09 0.000037
3 FBXW7 F-box and WD repeat domain containing 7 2580 131 0 0 2 0 1 1 4 4 4 8e-07 1 0.084 1.3e-06 0.0082
4 MAZ MYC-associated zinc finger protein (purine-binding transcription factor) 1659 771 0 0 0 0 0 2 2 2 1 0.0001 0.01 0.91 0.000015 0.064
5 PRUNE2 prune homolog 2 (Drosophila) 9339 3 0 0 0 0 0 4 4 3 3 0.0003 0.003 0.75 0.000018 0.064
6 LCE4A late cornified envelope 4A 304 151 0 0 0 0 0 3 3 2 2 0.00086 0.032 0.022 0.000022 0.068
7 WIF1 WNT inhibitory factor 1 1176 544 0 0 0 0 3 0 3 2 2 0.0021 0.001 0.61 3e-05 0.077
8 C10orf71 chromosome 10 open reading frame 71 4396 202 0 0 4 0 0 0 4 3 4 0.000052 0.058 0.64 0.000053 0.12
9 PPP2R1A protein phosphatase 2 (formerly 2A), regulatory subunit A , alpha isoform 1826 120 0 0 4 0 0 0 4 4 3 0.0029 0.015 0.2 0.00019 0.39
10 CDC27 cell division cycle 27 homolog (S. cerevisiae) 2565 189 0 0 1 1 0 0 2 2 2 0.00024 1 0.075 0.00034 0.63
11 FOS v-fos FBJ murine osteosarcoma viral oncogene homolog 1155 336 0 0 0 0 0 2 2 2 2 0.000056 1 0.92 0.00061 1
12 PIK3R2 phosphoinositide-3-kinase, regulatory subunit 2 (beta) 2243 66 0 0 3 0 0 0 3 3 3 0.00033 1 0.099 0.00071 1
13 PERP PERP, TP53 apoptosis effector 590 445 0 0 1 0 0 1 2 2 2 0.000077 1 0.98 0.00081 1
14 MSL3 male-specific lethal 3 homolog (Drosophila) 1692 1000 0 0 2 0 0 1 3 3 3 0.0001 1 0.37 0.001 1
15 RBMX RNA binding motif protein, X-linked 1265 306 0 0 2 1 0 0 3 2 3 0.00023 1 0.93 0.0021 1
16 RPGRIP1L RPGRIP1-like 4052 109 0 0 0 0 1 0 1 1 1 0.0024 NaN NaN 0.0024 1
17 PIK3CA phosphoinositide-3-kinase, catalytic, alpha polypeptide 3287 2 0 0 9 0 0 0 9 8 7 0.28 0.001 0.16 0.0032 1
18 MAGED1 melanoma antigen family D, 1 2557 50 0 0 0 0 0 1 1 1 1 0.0037 NaN NaN 0.0037 1
19 LOR loricrin 943 1 0 0 0 0 0 1 1 1 1 0.004 NaN NaN 0.004 1
20 CD96 CD96 molecule 1814 87 0 0 0 0 0 1 1 1 1 0.0042 NaN NaN 0.0042 1
21 FBXO10 F-box protein 10 2911 71 0 0 1 0 0 1 2 2 2 0.0005 1 0.89 0.0043 1
22 GAGE2C G antigen 2C 1485 11 0 0 0 0 1 0 1 1 1 0.0045 NaN NaN 0.0045 1
23 HSPC159 lectin, galactoside-binding-like 535 75 0 0 0 0 0 1 1 1 1 0.005 NaN NaN 0.005 1
24 TMEM196 transmembrane protein 196 533 11 0 0 0 0 0 1 1 1 1 0.005 NaN NaN 0.005 1
25 PIK3R1 phosphoinositide-3-kinase, regulatory subunit 1 (alpha) 2361 231 0 0 1 1 0 1 3 2 3 0.0019 1 0.25 0.0053 1
26 PRPF3 PRP3 pre-mRNA processing factor 3 homolog (S. cerevisiae) 2112 100 0 0 0 1 0 0 1 1 1 0.0055 NaN NaN 0.0055 1
27 GPR150 G protein-coupled receptor 150 1305 7 0 0 0 0 0 1 1 1 1 0.006 NaN NaN 0.006 1
28 ANKRD13C ankyrin repeat domain 13C 1674 527 0 0 2 0 0 0 2 2 2 0.00074 1 0.34 0.0061 1
29 TAF2 TAF2 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 150kDa 3700 355 0 0 0 0 1 0 1 1 1 0.0063 NaN NaN 0.0063 1
30 HESX1 HESX homeobox 1 570 20 0 0 0 0 1 0 1 1 1 0.0066 NaN NaN 0.0066 1
31 TMCO7 transmembrane and coiled-coil domains 7 3355 300 0 0 0 0 1 0 1 1 1 0.0068 NaN NaN 0.0068 1
32 MATR3 matrin 3 2596 60 0 0 0 0 0 1 1 1 1 0.0068 NaN NaN 0.0068 1
33 CENPV centromere protein V 837 65 0 0 0 0 0 1 1 1 1 0.007 NaN NaN 0.007 1
34 LYSMD2 LysM, putative peptidoglycan-binding, domain containing 2 656 81 0 0 1 0 0 0 1 1 1 0.007 NaN NaN 0.007 1
35 NANOS3 nanos homolog 3 (Drosophila) 583 78 0 0 0 0 0 1 1 1 1 0.007 NaN NaN 0.007 1
TP53

Figure S1.  Get High-res Image This figure depicts the distribution of mutations and mutation types across the TP53 significant gene.

PTEN

Figure S2.  Get High-res Image This figure depicts the distribution of mutations and mutation types across the PTEN significant gene.

FBXW7

Figure S3.  Get High-res Image This figure depicts the distribution of mutations and mutation types across the FBXW7 significant gene.

PRUNE2

Figure S4.  Get High-res Image This figure depicts the distribution of mutations and mutation types across the PRUNE2 significant gene.

LCE4A

Figure S5.  Get High-res Image This figure depicts the distribution of mutations and mutation types across the LCE4A significant gene.

Methods & Data
Methods

MutSig and its evolving algorithms have existed since the youth of clinical sequencing, with early versions used in multiple publications. [1][2][3]

"Three significance metrics [are] calculated for each gene, using the […] methods MutSigCV [4], MutSigCL, and MutSigFN [5]. These measure the significance of mutation burden, clustering, and functional impact, respectively […]. MutSigCV determines the P value for observing the given quantity of non-silent mutations in the gene, given the background model determined by silent (and noncoding) mutations in the same gene and the neighbouring genes of covariate space that form its 'bagel'. […] MutSigCL and MutSigFN measure the significance of the positional clustering of the mutations observed, as well as the significance of the tendency for mutations to occur at positions that are highly evolutionarily conserved (using conservation as a proxy for probably functional impact). MutSigCL and MutSigFN are permutation-based methods and their P values are calculated as follows: The observed nonsilent coding mutations in the gene are permuted T times (to simulate the null hypothesis, T = 108 for the most significant genes), randomly reassigning their positions, but preserving their mutational 'category', as determined by local sequence context. We [use] the following context categories: transitions at CpG dinucleotides, transitions at other C-G base pairs, transversions at C-G base pairs, mutations at A-T base pairs, and indels. Indels are unconstrained in terms of where they can move to in the permutations. For each of the random permutations, two scores are calculated: SCL and SFN, measuring the amount of clustering and function impact (measured by conservation) respectively. SCL is defined to be the fraction of mutations occurring in hotspots. A hotspot is defined as a 3-base-pair region of the gene containing many mutations: at least 2, and at least 2% of the total mutations. SFN is defined to be the mean of the base-pair-level conservation values for the position of each non-silent mutation […]. To determine a PCL, the P value for the observed degree of positional clustering, the observed value of SCL (computed for the mutations actually observed), [is] compared to the distribution of SCL obtained from the random permutations, and the P value [is] defined to be the fraction of random permutations in which SCL [is] at least as large as the observed SCL. The P value for the conservation of the mutated positions, PFN, [is] computed analogously." [6]

References
[1] Getz G, Höfling H, Mesirov JP, Golub TR, Meyerson M, Tibshirani R, Lander ES, Comment on "The Consensus Coding Sequences of Human Breast and Colorectal Cancers", Science 317(5844):1500b (2007)
[3] TCGA, Integrated genomic analyses of ovarian carcinoma, Nature 474(7353):609-615 (2011)
[4] Lawrence MS, et al., Mutational heterogeneity in cancer and the search for new cancer-associated genes, Nature 499(7457):214-218 (2013)
[6] Lawrence MS, et al., Discovery and saturation analysis of cancer genes across 21 tumour types, Nature 505(7484):495-501 (2014)