High frequency of loss of heterozygosity in vulval intraepithelial neoplasia (VIN) is associated with invasive vulval squamous cell carcinoma (VSCC)

Vulvar Lichen Sclerosus from Pathophysiology to Therapeutic Approaches: Evidence and Prospects

Vulvar lichen sclerosus (VLS) is a chronic, distressing, inflammatory disease with an enormous impact on quality of life. Treatment goals are relieving symptoms, reversing signs and preventing anatomical changes. Despite the availability of numerous therapeutic options, treatment outcome may not be entirely satisfactory and a definitive cure does not exist. This may be due to the fact that the exact VLS etiopathogenesis remains unknown. The objectives of this paper were to review the most up-to-date knowledge on VLS etiopathogenesis and to consider the available therapies through the lens of a plausible pathogenetic model. An electronic search on both VLS etiopathogenesis and its treatment was performed using the National Library of Medicine PubMed database. Based on current knowledge, it is conceivable that various, heterogeneous environmental factors acting on a genetic background trigger an autoimmune, Th-1 response, which leads to a chronic inflammatory state. This, in turn, can determine both tissue and micro-vascular injury and activation of signaling pathways involved in fibroblast and collagen metabolism. This pathogenetic sequence may explain the effectiveness of anti-inflammatory treatments, mostly topical corticosteroids, in improving VLS clinical-pathological changes. Further deepening of the disease pathways will presumably allow key mediators to become new therapeutic targets and optimize the available treatments.

A pre-existing coordinated inflammatory microenvironment is associated with complete response of vulvar high-grade squamous intraepithelial lesions to different forms of immunotherapy

Immunotherapy of vulvar high-grade squamous intraepithelial lesion (vHSIL) is investigated as an alternative for surgery, because of high comorbidity and risk of recurrence. Limited evidence exists on the role and composition of the immune microenvironment in current immunotherapeutic approaches for vHSIL. The vHSIL of 29 patients biopsied before treatment with imiquimod were analyzed by two multiplex seven-color immunofluorescence panels to investigate the pre-existing T-cell and myeloid cell composition in relation to treatment response. The samples were scanned with the Vectra multispectral imaging system. Cells were automatically phenotyped and counted with inForm advanced image analysis software. Cell counts and composition were compared to that of vHSIL patients before therapeutic vaccination (n = 29) and to healthy vulva (n = 27). Our data show that the immune microenvironment of complete responders (CR) to imiquimod resembled the coordinated infiltration with type 1 CD4⁺ and CD8⁺ T cells and CD14⁺ inflammatory myeloid cells also found in healthy vulva. However, more CD8⁺ T cells and FoxP3⁺ regulatory T cells were present in CR. The lesions of partial responders (PR) lacked such a coordinated response and displayed an impaired influx of CD14⁺ inflammatory myeloid cells. Importantly, complete responses after imiquimod or therapeutic vaccination showed the same dependency on a pre-existing coordinated type 1 T-cell and CD14⁺ myeloid cell infiltration. In conclusion, a good clinical outcome after two different forms of immunotherapy for vHSIL is associated with the presence of a primary inflammatory process resulting in the coordinated influx of several types of immune cells which is then amplified.

Pre-existing inflammatory immune microenvironment predicts the clinical response of vulvar high-grade squamous intraepithelial lesions to therapeutic HPV16 vaccination

BACKGROUND

Vulvar high-grade squamous intraepithelial lesion (vHSIL) is predominantly induced by high-risk human papilloma virus type 16 (HPV16). In two independent trials, therapeutic vaccination against the HPV16 E6 and E7 oncoproteins resulted in objective partial and complete responses (PRs/CRs) in half of the patients with HPV16+ vHSIL at 12-month follow-up. Here, the prevaccination and postvaccination vHSIL immune microenvironment in relation to the vaccine-induced clinical response was investigated.

METHODS

Two novel seven-color multiplex immunofluorescence panels to identify T cells (CD3, CD8, Foxp3, Tim3, Tbet, PD-1, DAPI) and myeloid cells (CD14, CD33, CD68, CD163, CD11c, PD-L1, DAPI) were designed and fully optimized for formalin-fixed paraffin-embedded tissue. 29 prevaccination and 24 postvaccination biopsies of patients with vHSIL, and 27 healthy vulva excisions, were stained, scanned with the Vectra multispectral imaging system, and automatically phenotyped and counted using inForm advanced image analysis software.

RESULTS

Healthy vulvar tissue is strongly infiltrated by CD4 and CD8 T cells expressing Tbet and/or PD-1 and CD14+HLA-DR+ inflammatory myeloid cells. The presence of such a coordinated pre-existing proinflammatory microenvironment in HPV16+ vHSIL is associated with CR after vaccination. In partial responders, a disconnection between T cell and CD14+ myeloid cell infiltration was observed, whereas clinical non-responders displayed overall lower immune cell infiltration. Vaccination improved the coordination of local immunity, reflected by increased numbers of CD4+Tbet+ T cells and HLA-DR+CD14+ expressing myeloid cells in patients with a PR or CR, but not in patients with no response. CD8+ T cell infiltration was not increased after vaccination.

CONCLUSION

A prevaccination inflamed type 1 immune contexture is required for stronger vaccine-induced immune infiltration and is associated with better clinical response. Therapeutic vaccination did not overtly increase immune infiltration of cold lesions.

Precursor lesions of vulvar squamous cell carcinoma - histology and biomarkers: A systematic review

The precursor lesion of vulvar squamous cell carcinoma (VSCC), namely vulvar intraepithelial neoplasia (VIN), is classified as: human papillomavirus (HPV)-related high grade squamous intraepithelial lesion (HSIL), and HPV-independent differentiated VIN (dVIN). Traditionally, histology and immunohistochemistry (IHC) have been the basis of diagnosis and classification of VIN. HSIL shows conspicuous histological atypia, and positivity on p16-IHC, whereas dVIN shows less obvious histological atypia, and overexpression or null-pattern on p53-IHC. For both types of VIN, other diagnostic immunohistochemical markers have also been evaluated. Molecular characterization of VIN has been attempted in few recent studies, and novel genotypic subtypes of HPV-independent VSCC and VIN have been identified. This systematic review appraises the VSCC precursors identified so far, focusing on histology and biomarkers (immunohistochemical and molecular). To gain further insights into the carcinogenesis and to identify additional potential biomarkers, gene expression omnibus (GEO) datasets on VSCC were analyzed; the results are presented.

Lichen Sclerosus: An autoimmunopathogenic and genomic enigma with emerging genetic and immune targets

Lichen sclerosus (LS) is an inflammatory dermatosis with a predilection for anogenital skin. Developing lesions lead to vulvar pain and sexual dysfunction, with a significant loss of structural anatomical architecture, sclerosis, and increased risk of malignancy. Onset may occur at any age in both sexes, but typically affects more females than males, presenting in a bimodal fashion among pre-pubertal children and middle-aged adults. A definitive cure remains elusive as the exact pathogenesis of LS remains unknown. A general review of LS, histologic challenges, along with amounting support for LS as an autoimmune disease with preference for a Th1 immune response against a genetic background is summarized. In addition to the classically referenced ECM1 (extracellular matrix protein 1), a following discussion of other immune and genetic targets more recently implicated as causative or accelerant agents of disease, particularly miR-155, downstream targets of ECM1, galectin-7, p53, and epigenetic modifications to CDKN2A, are addressed from the viewpoint of their involvement in three different, but interconnected aspects of LS pathology. Collectively, these emerging targets serve not only as inherently potential therapeutic targets for treatment, but may also provide further insight into this debilitating and cryptic disease.

Role of Human Papillomavirus in Vulvar Cancer

Human papillomavirus (HPV) is involved in one of the at least 2 pathways leading to vulvar squamous cell carcinoma (VSCC). Inactivation of p53 and retinoblastoma by the viral products E6 and E7 is involved in malignant transformation. The percentage of HPV-positive VSCCs ranges from 18% to 75%, depending on the geographical area. HPV-associated tumors affect relatively young women and arise from high-grade intraepithelial lesions, identical to other HPV-associated premalignant lesions of the anogenital tract. HPV-independent tumors tend to affect older women and usually arise in a background of inflammatory skin disorders and a subtle variant of in situ lesion called differentiated vulvar intraepithelial neoplasia. HPV-positive tumors tend to be of basaloid or warty types, whereas HPV-independent tumors tend to be of keratinizing type, but there is frequent overlap between histologic types. There is no conclusive evidence yet on the best strategy in terms of determining HPV attribution. HPV DNA detection is generally considered the gold standard although there is some concern about misclassification when using this technique alone. p16 immunostaining has shown to be an excellent surrogate marker of HPV infection. Positive results for both techniques are considered the best evidence for HPV-association. The prognostic role of HPV in VSCC is still contradictory, but increasing evidence suggests that HPV-associated tumors are less aggressive. Currently, there are no differences in treatment between HPV-associated and HPV-independent VSCC, but novel immunological strategies based on anti-HPV antigens are being evaluated in clinical trials.

The Natural History of Vulvar Intraepithelial Neoplasia, Differentiated Type: Evidence for Progression and Diagnostic Challenges

Squamous cell carcinoma of the vulva (SCCV) develops through either human papillomavirus (HPV)-dependent or HPV-independent pathways. Approximately 60% of SCCV arise independently of HPV, commonly in a background of an inflammatory dermatosis, particularly lichen sclerosus. The likely direct precursor to most of these lesions is vulvar intraepithelial neoplasia (VIN), differentiated type (dVIN), although the evidence is largely circumstantial. There are few reports of progression to carcinoma, and the natural history of this pathway is not well understood. Nevertheless, dVIN is widely regarded as a potentially aggressive lesion. We identified dVIN adjacent to SCCV in 97 of 212 women (45.8%). Twenty-four of the 97 women (24.7%) had biopsies performed at least 6 mo before presentation with SCCV; slides for 47 biopsies from 21 women were available for review. dVIN was identified in 18 biopsies from 8 women (38.1%), which in 14 biopsies had been previously unrecognized. The subsequent cancer developed in the same region as the previous biopsy showing dVIN in 6 of the 8 women. The median interval between biopsy and invasive cancer was 43.5 mo (range, 8-102 mo). dVIN-associated SCCV was strongly associated with both lichen sclerosus, and HPV-negative status compared with usual type VIN (relative risk=38.35 (9.755-150.8) and 0.06485 (0.02764-0.1522), respectively). This study adds to the evidence linking dVIN with SCCV, and indicates that both clinical and histologic underrecognition contribute to the apparent rarity of dVIN as a solitary diagnosis. The morphologic spectrum of dVIN is likely to be wider than commonly appreciated; however, histologically defining the lower threshold is difficult and controversial.

Genetic and epigenetic changes in vulvar squamous cell carcinoma and its precursor lesions: a review of the current literature

Vulvar cancer is a relatively rare gynecologic malignancy with an annual incidence in developed countries of approximately 2 per 100,000 women. Vulvar squamous cell carcinoma (VSCC) has two etiological pathways: a high risk human papillomavirus (HPV)-dependent route, which has usual vulvar intraepithelial neoplasia (uVIN) as a precursor lesion, and an HPV-independent route, which is associated with differentiated VIN (dVIN), lichen sclerosus, and genetic alterations, such as TP53 mutations. Research on the molecular etiology of vulvar cancer has increased in the past years, not only regarding genetic alterations, but also epigenetic changes. In genetic alterations, a mutation irreversibly changes the nucleotide sequence of the DNA, or the number of copies of chromosomes per cell is altered. In epigenetics, the nucleotide sequence remains the same but genes can be 'switched' on or off by, for example, DNA methylation or histone modification. We searched the current literature on genetic and epigenetic alterations in VSCC and its precursor lesions. Many studies have reported a higher incidence of somatic mutations in HPV-negative tumors compared to HPV-positive tumors, with TP53 mutations being the most frequent. Allelic imbalances or loss of heterozygosity are more frequently found in higher stages of dysplasia and in invasive carcinomas, but it is not exclusive to HPV-negative tumors. A limited number of studies are available on epigenetic changes in vulvar lesions, with hypermethylation of CDKN2A being the most frequently investigated change. For most genes, hypermethylation occurs more frequently in vulvar squamous cell carcinomas than in precursor lesions. As most studies have focused on HPV infection and TP53 mutations, we suggest that more research should be performed using whole genome or next generation sequencing to determine the true landscape of genetic and epigenetic alterations in vulvar squamous cell carcinoma.

High-resolution genomic profiling of human papillomavirus-associated vulval neoplasia

Background:

The incidence of human papillomavirus-associated vulval neoplasia is increasing worldwide; yet the associated genetic changes remain poorly understood.

Methods:

We have used single-nucleotide polymorphism microarray analysis to perform the first high-resolution investigation of genome-wide allelic imbalance in vulval neoplasia. Our sample series comprised 21 high-grade vulval intraepithelial neoplasia and 6 vulval squamous cell carcinomas, with paired non-lesional samples used to adjust for normal copy number variation.

Results:

Overall the most common recurrent aberrations were gains at 1p and 20, with the most frequent deletions observed at 2q, 3p and 10. Copy-neutral loss of heterozygosity at 6p was a recurrent event in vulval intraepithelial neoplasia. The pattern of genetic alterations differed from the characteristic changes we previously identified in cutaneous squamous cell carcinomas. Vulval neoplasia samples did not exhibit gain at 5p, a frequent recurrent aberration in a series of cervical tumours analysed elsewhere using an identical protocol.

Conclusion:

This series of 27 vulval samples comprises the largest systematic genome-wide analysis of vulval neoplasia performed to date. Despite shared papillomavirus status and regional proximity, our data suggest that the frequency of certain genetic alterations may differ in vulval and cervical tumours.

Presence and type of oncogenic human papillomavirus in classic and in differentiated vulvar intraepithelial neoplasia and keratinizing vulvar squamous cell carcinoma

The presence and type of oncogenic papillomavirus (HPV) in classic warty/basaloid vulvar intraepithelial neoplasia and in differentiated vulvar intraepithelial neoplasia and keratinizing vulvar squamous cell carcinoma was investigated using three techniques, that is, histology, in situ hybridization, and PCR-ELISA. HPV typing was performed using in situ hybridization and PCR-ELISA. Differentiated vulvar intraepithelial neoplasia and invasive keratinizing vulvar squamous cell carcinoma proved completely negative for HPV by PCR-ELISA, in situ hybridization, and histologic examination, while in classic vulvar intraepithelial neoplasia, a HPV positivity of 66.1% was found. HPV 16 was the predominant type, with HPV 35, 33, and 52 types found rarely and sometimes together with HPV 16. PCR-ELISA proved to be the most suitable method to detect and type mucosal oncogenic HPVs. The absolute absence of HPV DNA in differentiated vulvar intraepithelial neoplasias and in keratinizing vulvar squamous cell carcinoma suggests a strong HPV-independent pathway of malignant progression to invasive carcinoma.

The most common chromosome aberration detected by high-resolution comparative genomic hybridization in vulvar intraepithelial neoplasia is not seen in vulvar squamous cell carcinoma

We analyzed genetic changes in condylomas (four cases), vulvar intraepithelial neoplasia I-III (VIN I-III, eleven cases), and primary vulvar squamous cell carcinomas (VSCC, ten cases) by high-resolution comparative genomic hybridization (HR-CGH) and flowcytometry. All samples were also human papilloma virus (HPV)-genotyped. Gain of chromosome 1, the aberration most often seen in VIN III (67%), was not seen in HPV-positive or -negative VSCCs (0%). Both VIN III and VSCC frequently showed gain of 3q (56 and 70%, respectively). The VIN III samples often demonstrated gain of 20q (56%) and 20p (44%), and the VSCC samples gain of 8q (60%), loss of 3p (50%), and 8p (40%). None of the four most frequent changes in the VSCC samples occurred exclusively in the HPV-positive or -negative samples. As expected, we did not find any cytogenetic changes in condylomas and nearly any changes in VIN I-II.

Genomic rearrangements involving rDNA and centromeric heterochromatin in vulvar epidermoid carcinoma cell line A-431

The cytogenetic and molecular cytogenetic characterization of the human cell line A-431 derived from a vulvar epidermoid carcinoma is presented. A combination of karyotyping, fluorescence in situ hybridization (FISH) with chromosome- and/or region-specific probes, M-FISH, RxFISH, and comparative genomic hybridization (CGH) analysis was used. Six marker chromosomes with rearrangements involving insertions of single or double nucleolar organizing regions (NORs) and/or homogeneously staining regions containing active and overexpressed NORs and regions of centromeric heterochromatin were found: der(6), der(7), der(17), der(21), dic(13;14), and dic(14;18). The chromosomal origin of 14 other marker chromosomes was elucidated. Amplification of the C-MYC oncogene at 8q24 was revealed in two marker chromosomes: dup(8)(q24) and der(15)t(8;15)(q22;p11). Confirming previous reports, amplification of the cyclin D1 gene within an abnormal chromosome 11, that is, der(11)t(7;11)(p15;q21), was also detected. Loss of the TP53 tumor suppressor gene was evidenced over two der(17). Good concordance was found among karyotyping, FISH analysis, and CGH. Although reasons for NOR amplification or ectopic location in the epidermal carcinoma A-431 cell line are not clear yet, our data suggest that these phenomena play a supporting role with regard to other amplified genes. Thus, the A-431 cell line would be an appropriate model to study the different mechanisms involved in human tumorigenesis.

Immunohistochemical analysis of p53 in vulval intraepithelial neoplasia and vulval squamous cell carcinoma

Human papillomavirus (HPV) is thought to cause some vulval squamous cell carcinomas (VSCC) by degrading p53 product. Evidence on whether HPV-negative VSCC results from p53 mutation is conflicting. We performed immunohistochemistry for p53 product on 52 cases of lone vulval intraepithelial neoplasia (VIN), 21 cases of VIN with concurrent VSCC and 67 cases of VSCC. We had previously performed HPV detection and loss of heterozygosity (LOH) analyses on these samples. Abnormal p53 immunoreactivity (p53-positive) rates in HPV-positive VSCC and HPV-negative VSCC were 22% (12/54) and 31% (4/13), respectively (P<0.74). p53 immunoreactivity was associated with LOH at the p53 locus (P<0.004), but neither technique differentiated between HPV-positive and HPV-negative VSCC. p53 immunoreactivity was associated with overall LOH rates (p53-positive VSCC vs p53-negative VSCC mean fractional regional allelic loss 0.41 vs 0.24, respectively, P<0.027). LOH at 3p25 was more frequent in p53-positive VSCC cf p53-negative VSCC (70 vs 21%, respectively, P<0.007). There was a trend in p53 disruption associated with invasive disease; HPV-positive VSCC demonstrated more disruption than VIN associated with VSCC, which had more disruption than lone VIN III (22 vs 10 vs 0%, respectively, P<0.005). In all, three out of 73 cases of VIN were p53-positive. All three were associated with concurrent or previous VSCC. Meta-analysis of previous studies revealed significantly more p53 disruption in HPV-negative VSCC cf HPV-positive VSCC (58 vs 33%, respectively; P<0.0001). p53 immunoreactivity/mutation in VIN only appeared in association with VSCC. These data suggest that HPV-independent vulval carcinogenesis does not exclusively require disruption of p53, p53 disruption may work synergistically with LOH at specific loci and p53-positive VIN should be checked carefully for the presence of occult invasion.

Molecular evidence of a common clonal origin and subsequent divergent clonal evolution in vulval intraepithelial neoplasia, vulval squamous cell carcinoma and lymph node metastases

VIN is thought to be the precursor of some VSCCs because it is monoclonal, frequently occurs contiguously with VSCC and shares similar risk factors with a subgroup of VSCC. There has been no conclusive molecular evidence supporting this assumption. We performed X-chromosome inactivation analysis on 9 cases of lone VIN, 10 cases of VSCC and associated contiguous VIN and 11 cases of VSCC and associated noncontiguous VIN. Eight of the 9 cases of lone VIN appeared to be monoclonal. All 7 informative and monoclonal cases of VIN with contiguous VSCC and 6/9 informative cases of VIN with noncontiguous VSCC showed patterns of X-chromosome inactivation consistent with a common monoclonal origin for both VIN and VSCC. Two of the 9 cases of VIN with noncontiguous VSCC showed X-chromosome inactivation patterns consistent with a separate clonal origin. We performed LOH analysis at 6 chromosomal loci on these samples and 7 cases with lymph node metastases. Identical losses occurred 7 times in VIN and contiguous VSCC (random probability 1.2 x 10(-9)), twice in VIN and noncontiguous VSCC (random probability 1.5 x 10(-3)) and 3 times in VSCC and associated metastases (random probability 1.8 x 10(-5)). Some losses occurring in VSCC did not appear in the contiguous VIN or associated metastases and vice versa. These data provide molecular evidence that VIN is the precursor of VIN-associated VSCC, that multifocal disease may arise via either different clones or a single clone and that continued divergent clonal evolution may occur in vulval neoplasia.