Vulvar squamous cell carcinoma (SCC) consists of two different etiologic categories: human papilloma virus (HPV)-associated (HPV (+)) and HPV-non-associated (HPV (−)). There have been no genome-wide studies on the genetic alterations of vulvar SCCs or on the differences between HPV (+) and HPV (−) vulvar SCCs. In this study, we performed whole-exome sequencing and copy number profiling of 6 HPV (+) and 9 HPV (−) vulvar SCCs and found known mutations (TP53, CDKN2A and HRAS) and copy number alterations (CNAs) (7p and 8q gains and 2q loss) in HPV (−) SCCs. In HPV (+), we found novel mutations in PIK3CA, BRCA2 and FBXW7 that had not been reported in vulvar SCCs. HPV (−) SCCs exhibited more mutational loads (numbers of nonsilent mutations and driver mutations) than HPV (+) SCCs, but the CNA loads and mutation signatures between HPV (+) and HPV (−) SCCs did not differ. Of note, 40% and 40% of the 15 vulvar SCCs harbored PIK3CA and FAT1 alterations, respectively. In addition, we found that the SCCs harbored kataegis (a localized hypermutation) in 2 HPV (+) SCCs and copy-neutral losses of heterozygosity in 4 (one HPV (+) and 3 HPV (−)) SCCs. Our data indicate that HPV (+) and HPV (−) vulvar SCCs may have different mutation and CNA profiles but that there are genomic features common to SCCs. Our data provide useful information for both HPV (+) and HPV (−) vulvar SCCs and may aid in the development of clinical treatment strategies.

Although gene-to-gene analyses identified genetic alterations such as APC, KRAS and TP53 mutations in colon adenomas, it is largely unknown whether there are any others in them. Mutational profiling of high-grade colon adenoma (HGCA) that just precedes colon carcinoma might identify not only novel adenoma-specific genes but also critical genes for its progression to carcinoma. For this, we performed whole-exome sequencing (WES) of 12 HGCAs and identified 11 non-hypermutated and one hypermutated (POLE-mutated) cases. We identified 22 genes including APC, KRAS, TP53, GNAS, NRAS, SMAD4, ARID2, and PIK3CA with non-silent mutations in the cancer Census Genes. Bi-allelic and mono-allelic APC alterations were found in nine and one HGCAs, respectively, while the other two harbored wild-type APC. Five HGCAs harbored either mono-allelic (four HGCAs) or bi-allelic (one HGCA) SMAD4 mutation or 18q loss that had been known as early carcinoma-specific changes. We identified MTOR, ACVR1B, GNAQ, ATM, CNOT1, EP300, ARID2, RET and MAP2K4 mutations for the first time in colon adenomas. Our WES data is largely matched with the earlier ‘adenoma-carcinoma model’ (APC, KRAS, NRAS and GNAS mutations), but there are newly identified SMAD4, MTOR, ACVR1B, GNAQ, ATM, CNOT1, EP300, ARID2, RET and MAP2K4 mutations in this study. Our findings provide resource for understanding colon premalignant lesions and for identifying genomic clues for differential diagnosis and therapy options for colon adenomas and carcinomas.

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder mainly associated with altered genomic imprinting at chromosome 11p15.5. Children with BWS, especially uniparental disomy (UPD) at 11p15.5, are at increased risk of embryonal tumors including hepatoblastoma. Although genetic alterations of sporadic hepatoblastomas have been identified, integrated germline and somatic alterations of BWS-related hepatoblastoma have not been reported. For this, we performed whole-exome sequencing and genome-wide loss of heterozygosity/copy number analyses using a single nucleotide polymorphism (SNP) array for a hepatoblastoma in a BWS infant with paternal UPD at chromosome 11p15.5. We found germline 11p15.5 UPD as well as germline mutations of APC and PALB2 in the patient. At the somatic level, we found a CTNNB1 hotspot mutation and chromosome 1q gain in the tumor. The development of hepatoblastoma in this case might be explained by predisposition of the germline events (11p15.5 UPD, mutations of APC and PALB2) and later by somatic events with CTNNB1 somatic mutation and 1q gain. To our knowledge, this is the first report of germline and somatic genomic alteration profiles in hepatoblastoma arising from BWS. Clinically, our results provide a rationale for performing a more strict and intense protocol for hepatoblastoma surveillance in a high-risk BWS infant, such as the UPD-carrying case, for early detection and treatment.

Little is known about genomic alterations of gestational choriocarcinoma (GC), unique cancer that originates in pregnant tissues, and the progression mechanisms from the nonmalignant complete hydatidiform mole (CHM) to GC. Whole-exome sequencing (20 GCs) and/or single-nucleotide polymorphism microarray (29 GCs) were performed. We analyzed copy-neutral loss-of-heterozygosity (CN-LOH) in 29 GCs that exhibited androgenetic CN-LOHs (20 monospermic, 8 dispermic) and no CN-LOH (one with NLRP7 mutation). Most GCs (25/29) harboring recurrent copy number alterations (CNAs) and gains on 1q21.1-q44 were significantly associated with poor prognosis. We detected five driver mutations in the GCs, most of which were chromatin remodeling gene (ARID1A, SMARCD1, and EP300) mutations but not in common cancer genes such as TP53 and KRAS. One patient’s serial CHM/invasive mole/GC showed consistent CN-LOHs, but only the GC harbored CNAs, indicating that CN-LOH is an early pivotal event in HM-IM-GC development, and CNAs may be a late event that promotes CHM progression to GC. Our data indicate that GCs have unique profiles of CN-LOHs, mutations and CNAs that together differentiate GCs from non-GCs. Practically, CN-LOH and CNA profiles are useful for the molecular diagnosis of GC and the selection of GC patients with poor prognosis for more intensive treatments, respectively.

Gastric adenoma (GA) is a premalignant lesion that precedes intestinal-type gastric carcinoma (GC). However, genetic progression mechanisms from GA to GC have not been clarified. We performed whole-exome sequencing-based mutational analyses for 15 synchronous pairs of attached GAs and GCs. There was no significant difference in the number of driver mutations or copy-number alterations between GAs and GCs. Well-known mutations of and were recurrently detected in synchronous GA/GC pairs. In addition, we discovered novel and mutations and hypermutation in GAs, but did not identify recurrent drivers for GA-to-GC progression. Clonal structure analyses revealed that most GA/GC pairs exhibit parallel evolution with early divergence rather than stepwise evolution during GA-to-GC progression. Of note, three cases were identified as clonally nonrelated GA/GC pairs despite the lack of histologic differences. We found differences in dominant mutational signatures 1, 6, 15, and 17 in GA/GC trunks, GA branches, and GC branches. Compared with our previous work on synchronous colon adenoma/carcinoma genome structures, where most drivers were in the trunk with parallel evolution, synchronous GA/GC genomes showed a different model of parallel evolution, with many drivers in the branches. The preferred sequence of mutational events during GA-to-GC progression might be more context-dependent than colon adenoma progression. Our results show that nonclonal synchronous GA/GC is common and that GA genomes have already acquired distinct genomic alterations, suggesting caution in the diagnosis of synchronous GA and GC, especially in residual or recurrent cases. .