| Literature DB >> 29872726 |
My Linh Thibodeau1,2, Melika Bonakdar2, Eric Zhao2, Karen L Mungall2, Caralyn Reisle2, Wei Zhang2, Morgan H Bye2, Nina Thiessen2, Dustin Bleile2, Andrew J Mungall2, Yussanne P Ma2, Martin R Jones2, Daniel J Renouf3, Howard J Lim3, Stephen Yip4, Tony Ng4, Cheryl Ho3, Janessa Laskin2,3, Marco A Marra1,2, Kasmintan A Schrader5, Steven J M Jones1,2.
Abstract
Eccrine porocarcinomas (EPs) are rare malignant tumours of the intraepidermic sweat gland duct and most often arise from benign eccrine poromas. Some recurrent somatic genomic events have been identified in these malignancies, but very little is known about the complexity of their molecular pathophysiology. We describe the whole genome and whole transcriptome genomic profiling of a metastatic EP in a 66-year-old male patient with a previous history of localized porocarcinoma of the scalp. Whole genome and whole transcriptome genomic profiling was performed on the metastatic EP. Whole genome sequencing was performed on blood-derived DNA in order to allow a comparison between germline and somatic events. We found somatic copy losses of several tumour suppressor genes including APC, PTEN and CDKN2A, CDKN2B and CDKN1A. We identified a somatic hemizygous CDKN2A pathogenic splice site variant. De novo transcriptome assembly revealed abnormal splicing of CDKN2A p14ARF and p16INK4a. Elevated expression of oncogenes EGFR and NOTCH1 was noted and no somatic mutations were found in these genes. Wnt pathway somatic alterations were also observed. In conclusion, our results suggest that the molecular pathophysiology of malignant EP features high complexity and subtle interactions of multiple key genes. Cell cycle dysregulation and CDKN2A loss of function was found to be a new potential driver in EP tumourigenesis. Moreover, the combination of somatic copy number variants and abnormal gene expression perhaps partly related to epigenetic mechanisms, all likely contribute to the development of this rare malignancy in our patient.Entities:
Year: 2018 PMID: 29872726 PMCID: PMC5871832 DOI: 10.1038/s41698-018-0050-5
Source DB: PubMed Journal: NPJ Precis Oncol ISSN: 2397-768X
Fig. 1Histology and immunochemistry profile of poroid neoplasm. a Hematoxylin & eosin (H&E) stained section of primary scalp lesion. b H&E-stained section of subsequent metastatic left neck lesion. c H&E-stained section of subsequent metastatic cerebellar tumour. Immunohistochemistry of the cerebellar tumour for d CK5, e β-catenin, f p16, g EGFR, and h p53. All images are shown at 200× magnification
Fig. 2CDKN2A splicing. a CDKN2A (p14ARF/p16INK4a) normal splicing. b CDKN2A exon 2 skipping caused by the somatic splice site mutation (p14ARFc.194-1G>A, NM_05895.3; p16INK4a c.151-1G>A, NM_000077.4). c CDKN2A (p14) abnormal splicing caused by the c.194−1G>A (NM_058195.3) somatic mutation leading to 1 base pair deletion and a frameshift
RNA expression metrics of selected genes (diploid model)
| Gene | Copy number change (diploid model) | All TCGA | ESCA_SCC TCGA | All TCGA (matched normal) | Bodymap | |||
|---|---|---|---|---|---|---|---|---|
| %ile | kIQR | %ile | kIQR | %ile | kIQR | Mean FC | ||
|
| −1 (DLOH) | 84 | 1.1 | 70 | 0.41 | 86 | 0.88 | −1.17 |
|
| −1 (DLOH) | 1 | −1.5 | 0 | −1.77 | 0 | −2.33 | −1.79 |
|
| 0 | 94 | 1.7 | 79 | 0.73 | 100 | 2.06 | 1.25 |
|
| 0 | 2 | −0.96 | 4 | −1.1 | 13 | −0.91 | 1.48 |
|
| 0 | 96 | 4.25 | 89 | 1.08 | 100 | 9.78 | 7.59 |
|
| −1 (DLOH) | 60 | 0.2 | 56 | 0.06 | 56 | 0.11 | 1.44 |
|
| −1 (DLOH) | 60 | 0.15 | 72 | 0.56 | 99 | 4.35 | 4.67 |
|
| −1 (DLOH) | 96 | 3.74 | 90 | 1.43 | 91 | 1.78 | 3.91 |
|
| −1 (DLOH) | 86 | 1.06 | 97 | 2.49 | 91 | 1.5 | 1.73 |
|
| 0 | 65 | 0.28 | 56 | 0.1 | 53 | 0.04 | −1.59 |
|
| 0 | 95 | 1.91 | 100 | 3.36 | 95 | 1.3 | −1.01 |
|
| 0 | 31 | −0.3 | 9 | −0.73 | 92 | 1.5 | 1.98 |
|
| 0 | 46 | −0.08 | 6 | −0.99 | 82 | 2.24 | 1.45 |
|
| −1 (DLOH) | 48 | −0.03 | 47 | −0.05 | 91 | 1.13 | 1.09 |
|
| 0 | 99 | 17.91 | 93 | 3.62 | 100 | 29.5 | 16.72 |
|
| 0 | 22 | −0.47 | 3 | −0.68 | 10 | −0.79 | 1.77 |
|
| 0 | 42 | −0.14 | 14 | −0.63 | 90 | 2.35 | 1.57 |
|
| 0 | 90 | 2.28 | 92 | 2.15 | 92 | 1.97 | 3.21 |
|
| 0 | 97 | 2.78 | 53 | 0.04 | 100 | 3.95 | 5.25 |
|
| 0 | 98 | 5.58 | 93 | 1.52 | 97 | 4.43 | 4.18 |
|
| +2 (ASCNA) | 100 | 5.08 | 97 | 2.22 | 100 | 8.58 | 3.62 |
|
| 0 | 7 | −0.69 | 0 | −1.09 | 14 | −0.7 | 1.05 |
|
| 0 | 99 | 5.62 | 83 | 1.02 | 100 | 8.97 | 6.42 |
|
| 0 | 96 | 2.45 | 90 | 1.24 | 100 | 4.41 | 1.83 |
|
| 0 | 97 | 3.31 | 97 | 4.19 | 99 | 5.89 | 2.86 |
|
| 0 | 93 | 2.08 | 90 | 2.07 | 100 | 3.26 | −1.07 |
|
| 0 | 1 | −0.97 | 2 | −1.37 | 5 | −0.91 | −1.14 |
|
| 0 | 96 | 3.16 | 82 | 0.96 | 100 | 4.81 | 5.35 |
|
| +2 (ASCNA) | 89 | 1.19 | 82 | 0.98 | 87 | 1.05 | 1.76 |
|
| −1 (DLOH) | 80 | 0.69 | 76 | 0.64 | 66 | 0.33 | 1.14 |
|
| 0 | 95 | 1.82 | 64 | 0.29 | 100 | 3.31 | 2.26 |
|
| 0 | 64 | 0.29 | 56 | 0.16 | 89 | 1.19 | 1.75 |
|
| 0 | 79 | 0.73 | 18 | −0.49 | 94 | 1.75 | 1.77 |
|
| 0 | 94 | 1.79 | 90 | 1.45 | 97 | 2.05 | 1.86 |
|
| 0 | 99 | 3.84 | 100 | 6.67 | 81 | 0.82 | 1.15 |
|
| 0 | 96 | 8.33 | 89 | 1.54 | 100 | 14.41 | 18.52 |
|
| −1 (DLOH) | 83 | 1.09 | 33 | −0.13 | 91 | 2.12 | 2.9 |
TCGA The Cancer Genome Atlas, ASCNA allele-specific copy number alteration, DLOH deletion loss of heterozygosity, ESCA_SCC oesophageal squamous cell carcinoma, FC fold change, kIQR number of inter-quartile range intervals away from the median, %ile percentile