Comparison of HER2 gene amplification and KRAS alteration in eyelid sebaceous carcinomas with that in other eyelid tumors

Epidemiology and tumor microenvironment of ocular surface and orbital tumors on growth and malignant transformation

The ocular surface and orbit constitute unique microenvironments in the human body. Current advances in molecular research have deepened our understanding of tumor development in these regions. Tumors exhibit greater heterogeneity compared to normal tissues, as revealed by pathological and histological examinations. The tumor microenvironment (TME) plays a crucial role in the proliferation and progression of cancer cells. Factors from the external environment or the body's own inflammation and microcirculation interact within the TME, maintaining a delicate balance. Disruption of this balance, through uncontrolled signal pathway activation, can transform normal or benign tissues into malignant ones. In recent years, various systemic immunotherapies have been developed for cancer treatment. This study reviews the epidemiology of ocular surface and orbital tumors include squamous cell carcinoma, basal cell carcinoma, sebaceous carcinoma and lymphoma in conjunction with their occurrence, growth, and underlying mechanisms. We propose that by examining clinical histopathological images, we can identify specific and shared microscopic features of tumors. By collecting, classifying, and analyzing data from these clinical histopathological images, we can pinpoint independent diagnostic factors characteristic of tumors. We hope this study provides a basis for future exploration of the mechanisms underlying different ocular diseases.

HPV-Associated Squamous Cell Carcinoma of the Eyelid: Diagnostic Utility of p16 Immunohistochemistry and mRNA In Situ Hybridization

BACKGROUND

High-risk (HR) Human papillomavirus (HPV) has been implicated in pathogenesis of squamous cell carcinomas (SCC) at several sites with mucocutaneous junctions, including the head and neck. SCC is the second most common eyelid malignancy. However, its association with transcriptionally active HR-HPV has not been adequately studied.

METHODS

Two index cases of eyelid HPV-associated SCC are described in detail. A retrospective cohort of eyelid SCC was examined for p16 immunoexpression. Cases demonstrating p16 positivity or equivocal staining were subjected to high-risk HPV mRNA in situ hybridization (ISH). Quantitative real-time PCR (qPCR) was performed in mRNA ISH-positive cases for HPV genotyping.

RESULTS

The two index patients were older adult females, with upper eyelid tumours. On histology, both tumours were non-keratinizing SCC with trabecular and nested architecture reminiscent of oropharyngeal HPV-associated non-keratinizing SCC, prompting p16 immunohistochemistry, which was positive. HR-HPV mRNA ISH was positive, and qPCR detected HPV16 in both cases. Three of 20 (15%) archival cases showed p16 immunopositivity and two (10%) showed equivocal staining. However, mRNA ISH was negative. All cases showing p16 immunostaining and lacking HR-HPV were keratinizing SCCs. Thus, 9% of all eyelid SCC examined demonstrated HR-HPV.

CONCLUSION

The prevalence of HR-HPV in eyelid SCC is low in Indian patients. HPV-associated SCC may mimic commoner eyelid carcinomas as it lacks overt keratinization. In basaloid-appearing eyelid carcinomas, p16 immunopositivity should be followed by reflex HR-HPV mRNA ISH, as p16 immunohistochemistry alone has low specificity. The prognostic role, if any, of HPV association needs further evaluation.

Prevalence of human papillomavirus in eyelid carcinoma among Koreans: a clinicopathological study

BACKGROUND

Human papillomavirus (HPV) has been detected in eyelid sebaceous gland carcinoma (SGC) and squamous cell carcinoma (SCC), and detection rates greatly varied across studies. This study aimed to investigate the presence of HPV in eyelid SGC and SCC among Koreans and its correlation with clinicopathological characteristics.

METHODS

Surgically resected eyelid samples diagnosed as SGC or SCC from January 1999 to June 2011 were identified from the pathology database of three referral centres in Korea. Clinicopathological information including origin (skin vs. tarsal conjunctiva) and treatment outcomes were retrospectively reviewed. Immunohistochemistry (IHC) for p16, HPV DNA in situ hybridisation (ISH), and polymerase chain reaction-based DNA microarray were performed in paraffin-embedded tissue sections.

RESULTS

Our cohort included 34 SGC and 12 SCC cases with Asian ethnicity. HPV was detected in 4 SGC and 6 SCC by DNA microarray, while 2 SCC (16.7%) showed positivity in ISH. SCC of tarsal conjunctival origin was significantly more common in HPV-positive SCC than in HPV-negative SCC (5 of 6 vs. 0 of 6, P = 0.015, Fisher's exact test). Among samples showing positive staining in p16 IHC, HPV positivity rates were 0.0% (0/19) in SGC and 100% (3/3) in SCC. There was no significant difference in overall and local recurrence rate in eyelid SGC and SCC according to the HPV status (P > 0.99).

CONCLUSIONS

HPV was found in a subset of eyelid SGC and SCC among Koreans and might be aetiologically related to SCC of tarsal conjunctival origin. Overexpression of p16 is considered to be inappropriate as an indicator of HPV infection in eyelid SGC. Further investigation is required to elucidate the transmission route and pathogenic roles of HPV.

Adamantinoma-Like Ewing Sarcoma of the Head and Neck: A Case-Series of a Rare and Challenging Diagnosis

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignant tumor characterized by EWSR1::FLI1 related fusions and complex epithelial differentiation. ALES poses a tremendous diagnostic challenge owing to its resemblance to a wide variety of common head and neck malignancies. We aimed to study the clinicopathologic spectrum of ALES diagnosed at our institute. A retrospective review of the clinical and pathologic features of all EWSR1-rearranged ALES cases was performed after confirming the diagnosis. The cases lacking EWSR1 rearrangement were excluded. A total of 7 patients were analyzed. The median age was 27 years (range 7-42 years). There were 4 males and 3 female patients. Tumors were distributed as follows: maxilla (n = 2), parotid (n = 2), nasal cavity (n = 1), ethmoid/maxilla (n = 1), and thyroid (n = 1). Tumor size ranged from 2.2 to 5.5 cm. On microscopy, tumors displayed nested-lobular architecture, monomorphic cells, and interlobular fibrotic stroma. Other features included: palisading (n = 5), squamous differentiation (n = 2), keratinization (n = 1), colonisation of salivary ducts (n = 1) and thyroid follicles (n = 1), follicle-like cysts (n = 3), calcification (n = 2), necrosis (n = 3). Mitotic rate was 4-15/2 mm². On immunohistochemistry, cytokeratins (100%), p40 (100%), strong/diffuse membranous CD99 (100%), NKX2.2 (100%), Fli-1 (71%), and synaptophysin (71%) was positive. Patients received chemotherapy (n = 7) and radiotherapy (n = 4). Two patients developed recurrence at 6 and 10 months; 3 developed metastases at 0, 6, and 25 months. ALES is a rare and aggressive malignancy that mimics diverse neoplasms common in the head and neck region. Awareness of the morphologic and immunohistochemistry spectrum of this tumor is essential to avoid diagnostic errors.

Human Papillomavirus Related Neoplasia of the Ocular Adnexa

Human papillomaviruses (HPV) are a large group of DNA viruses that infect the basal cells of the stratified epithelium at different anatomic locations. In the ocular adnexal region, the mucosa of the conjunctiva and the lacrimal drainage system, as well as the eyelid skin, are potential locations for HPV-related neoplasia. The role of HPV in squamous cell neoplasia of the ocular adnexa has been debated for several decades. Due to the rarity of all these tumors, large studies are not available in the scientific literature, thereby hampering the precision of the HPV prevalence estimates and the ability to conclude. Nevertheless, increasing evidence supports that defined subsets of conjunctival papillomas, intraepithelial neoplasia, and carcinomas develop in an HPV-dependent pathway. The role of HPV in squamous cell tumors arising in the lacrimal drainage system and the eyelid is still uncertain. Further, the potential of HPV status as a diagnostic, prognostic, or predictive biomarker in these diseases is a topic for future research.

New Targeted Therapies and Immunotherapies for Locally Advanced Periocular Malignant Tumours: Towards a New 'Eye-Sparing' Paradigm?

The management of periocular skin malignant tumours is challenging. Surgery remains the mainstay of treatment for localised eyelid cancers. For more locally advanced cancers, especially those invading the orbit, orbital exenteration has long been considered the gold standard; however, it is a highly disfiguring and traumatic surgery. The last two decades have been marked by the emergence of a new paradigm shift towards the use of 'eye-sparing' strategies. In the early 2000s, the first step consisted of performing wide conservative eyelid and orbital excisions. Multiple flaps and grafts were needed, as well as adjuvant radiotherapy in selected cases. Although being incredibly attractive, several limitations such as the inability to treat the more posteriorly located orbital lesions, as well as unbearable diplopia, eye pain and even secondary eye loss were identified. Therefore, surgeons should distinguish 'eye-sparing' from 'sight-sparing' strategies. The second step emerged over the last decade and was based on the development of targeted therapies and immunotherapies. Their advantages include their potential ability to treat almost all tumours, regardless of their locations, without performing complex surgeries. However, several limitations have been reported, including their side effects, the appearance of primary or secondary resistances, their price and the lack of consensus on treatment regimen and exact duration. The aim of this article was to review the evolution of the management of locally advanced periocular malignant tumours over the last three decades and highlight the new paradigm shift towards the use of 'eye-sparing' strategies.

Molecular Genetics of Sebaceous Neoplasia

Sebaceous neoplasia primarily includes sebaceous adenoma, sebaceoma, and sebaceous carcinoma (SC). Sebaceous adenoma, sebaceoma, and a subset of cutaneous SC are frequently associated with defective DNA mismatch repair resulting from mutations in MLH1, MSH2, or MSH6. These tumors can be sporadic or associated with Muir-Torre syndrome. SCs without defective DNA mismatch repair have ultraviolet signature mutation or paucimutational patterns. Ocular SCs have low mutation burdens and frequent mutations in ZNF750. Some ocular sebaceous carcinomas have TP53 and RB1 mutations similar to cutaneous SC, whereas others lack such mutations and are associated with human papilloma virus infection.

High-risk human papillomavirus and ZEB1 in ocular adnexal sebaceous carcinoma

BACKGROUND

Ocular adnexal (OA) sebaceous carcinoma is an aggressive malignancy. Oncologic drivers of ocular sebaceous carcinoma are incompletely understood.

METHODS

A retrospective search of our pathology archives for OA sebaceous carcinoma identified 18 primary resection specimens. Immunohistochemistry for p16 and ZEB1 and RNA in situ hybridization for high-risk human papillomavirus (HPV) subtypes were performed.

RESULTS

High-risk HPV was demonstrated in 2/11 (18%) cases. p16 overexpression was observed in 10/11 (91%). No association between gender, age at presentation, tumor location, intraepithelial spread, tumor size, and T stage was observed between HPV-driven and nonviral cases. High expression of ZEB1 was observed in the intraepithelial component of 4/14 (28%) cases and in the subepithelial component of 1/13 (7%) cases. ZEB1 overexpression was not associated with HPV status, T stage, or tumor size.

CONCLUSION

As previously described by others, our findings suggest that a subset of OA sebaceous carcinomas may arise via an HPV-dependent pathway. However, unlike high-risk HPV-driven carcinomas of the oropharynx, we did not identify an association between HPV-status and prognostic features. Furthermore, p16 expression was not a useful surrogate marker for HPV-driven disease. ZEB1 overexpression is not associated with HPV in our cohort of ocular sebaceous carcinoma.

Sebaceous Carcinoma Incidence and Survival Among Solid Organ Transplant Recipients in the United States, 1987-2017

Importance

Risk of sebaceous carcinoma (SC), a rare skin cancer associated with Muir-Torre syndrome, is elevated among solid organ transplant recipients (SOTRs). However, population studies evaluating this association and assessing survival for posttransplant cases are lacking, and further understanding of SC epidemiology in this immunosuppressed population could provide etiologic and clinical insights.

Objective

To assess SC incidence and patient survival after solid organ transplantation.

Design, Setting, and Participants

This cohort study, conducted from January 1, 1987, to December 31, 2017, used data from the Transplant Cancer Match Study, which links transplant and cancer registry data for 17 states and 1 metropolitan area in the United States. Altogether, these registries account for approximately 46% of all US transplants. Data on demographic and transplant characteristics as well as induction and initial maintenance immunosuppressive therapies were obtained from the transplant registry. Standardized incidence ratios (SIRs) comparing SC incidence among SOTRs to the general population were calculated. Incidence rate ratios (IRRs) comparing SC risk between SOTR subgroups were calculated using multivariate Poisson regression. Cox regression was used to compare overall survival between SC cases in SOTRs and other individuals.

Main Outcomes and Measures

Sebaceous carcinoma incidence and overall patient survival after transplantation compared with the general population.

Results

A total of 326 282 transplant procedures were performed for 301 075 patients (No. [%] age at transplant, 126 550 [38.8%] aged 0-44 years; 82 394 [25.3%] aged 45-54 years; 82 082 [25.5%] aged 55-64 years; 35 256 [10.8%] aged ≥65 years; 201 354 male patients [61.7%]; 202 557 White patients [62.1%]). A total of 102 SCs were diagnosed in 301 075 SOTRs, corresponding to a 25-fold increased incidence (SIR, 24.8; 95% CI, 20.2-30.1). Incidence was especially elevated among lung recipients (SIR, 47.7; 95% CI, 20.6-94.0) and after a posttransplant diagnosis of cutaneous squamous cell carcinoma (SIR, 104.0; 95% CI, 62.8-163.0). Among SOTRs, factors independently associated with SC risk included male sex (IRR, 2.46; 95% CI, 1.48-4.07; P < .001), race/ethnicity (non-Hispanic Black vs non-Hispanic White, IRR, 0.28; 95% CI, 0.10-0.77; P = .01), older age (IRR, 7.85; 95% CI, 3.85-16.0; ≥65 vs 0-44 years; P < .001 for trend), use of thymoglobulin induction (IRR, 1.82; 95% CI, 1.16-2.86; P = .009), posttransplant cutaneous squamous cell carcinoma (IRR, 4.60; 95% CI, 2.67-7.94; P < .001), and longer time since transplant (IRR, 8.40; 95% CI, 3.94-17.90; ≥10 vs 0-1.9 years; P < .001 for trend). Muir-Torre syndrome-associated cancers were rare among both SOTRs and others with SC (3.3%-4.1%). Among patients with SC, prior transplantation was associated with increased overall mortality (adjusted hazard ratio, 2.09; 95% CI, 1.45-3.01), although few deaths were attributed to SC (4 of 92 SOTRs [4.3%]; 235 of 3585 non-SOTRs [6.6%]).

Conclusions and Relevance

Among SOTRs, results of this large cohort study suggest that SC was associated with measures of immunosuppression, and overall survival was worse than for other patients with SC. Findings also suggest a possible role for UV radiation in carcinogenesis.

Sebaceous Carcinoma Epidemiology and Genetics: Emerging Concepts and Clinical Implications for Screening, Prevention, and Treatment

Sebaceous carcinoma is an aggressive skin cancer with a 5-year overall survival rate of 78% for localized/regional disease and 50% for metastatic disease. The incidence of this cancer has been increasing in the United States for several decades, but the underlying reasons for this increase are unclear. In this article, we review the epidemiology and genetics of sebaceous carcinoma, including recent population data and tumor genomic analyses that provide new insights into underlying tumor biology. We further discuss emerging evidence of a possible viral etiology for this cancer. Finally, we review the clinical implications of recent advances in sebaceous carcinoma research for screening, prevention, and treatment.

CDKN2A, CDK1, and CCNE1 overexpression in sebaceous gland carcinoma of eyelid

PURPOSE

To investigate the overexpression of genes in sebaceous gland carcinoma (SGC) of the eyelid compared to sebaceous adenoma of the eyelid in order to elucidate the molecular mechanism underlying pathogenesis.

METHODS

We performed histopathological examination of eyelid tissues surgically removed from four patients diagnosed with SGC (cases 1-3) and sebaceous adenoma (case 4) of the eyelid. Next, we performed global gene expression analysis of surgical tissue samples using a GeneChip^® system and the Ingenuity Pathways Knowledge Base. The results of the GeneChip^® analysis were explored with quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

In the SGC samples, we found that 211, 199, and 199 genes, respectively, showed ≥ 2.0-fold higher expression than those in the sebaceous adenoma sample (case 4); 194 genes were common to all three SGC samples. For the 194 genes with upregulated expression, functional category analysis showed that SGC of the eyelid employed a unique gene network, including cyclin-dependent kinase inhibitor 2A (CDKN2A), cyclin-dependent kinase 1 (CDK1), and cyclin E1 (CCNE1), which are related to cell cycle progression, incidence of tumor, and cell viability. Furthermore, qRT-PCR analysis showed that the expression levels of CDKN2A, CDK1, and CCNE1 were significantly upregulated in all SGC cases compared to those in the sebaceous adenoma case. These data were similar to the results of microarray analysis.

CONCLUSION

Overexpression of cell cycle-related genes CDKN2A, CDK1, CCNE1, and their gene network may help elucidate the pathogenic pathway of SGC of the eyelid at the molecular level.

Human papillomavirus in ocular malignant tumours: a study from a tertiary eye care centre in North India

OBJECTIVE

The present study aims to detect the presence of human papillomavirus (HPV) in ocular malignant tumours, including retinoblastoma, eyelid squamous cell carcinoma (SCC), and sebaceous gland carcinoma (SGC), in the North Indian population.

DESIGN

Prospective observational non randomized study.

PARTICIPANTS

In this study, 142 prospective cases of ocular malignant tumours (retinoblastoma, SGC, and SCC) were included.

METHODS

HPV was detected by multiplex PCR using PGMY09/11 primers in 142 patients with ocular malignancies. This was followed by genotyping using linear array (reverse hybridization).

RESULTS

Of the 142 tumours studied, 72 were retinoblastoma, 30 SGC, and 40 SCC. The HPV genome was detected in 2.8% (4 of 142) of cases by multiplex PCR; all positive cases (4 of 40) were SCC. Genotyping revealed that all positives belonged to the high-risk HPV16 genotype. HPV-positive SCC patients had better disease-free survival. Retinoblastoma and SGC cases were negative for HPV.

CONCLUSIONS

Low prevalence of HPV in ocular malignancies was observed in this study. The HPV genome was detected only in ocular squamous cell carcinoma cases and these patients were associated with better prognosis. HPV may not have a role in retinoblastoma and SGC in the North Indian population.

Updates on the clinical diagnosis and management of ocular sebaceous carcinoma: a brief review of the literature

Ocular sebaceous carcinoma (SC) is an exceedingly rare but aggressive malignancy that can impair patients’ visual acuity or even cause tumor-specific mortality. This tumor usually mimics chronic benign eyelid lesions, thus leading to delayed diagnosis, thereby causing high recurrence and metastasis. Ophthalmologists should be more aware of SC in order to offer correct diagnosis and treatment at the onset of symptoms. Prompt surgical excision with frozen section margin control is the mainstay of SC management after patient evaluation and accurate biopsy. Mohs micrographic surgery has been associated with better tumor control outcomes than wide local excision. Radiation therapy should be considered as adjuvant treatment for locally advanced (stage T3a or higher) or high-risk (pagetoid spread) SC, nodal metastasis, or palliative care. Cryotherapy and topical chemotherapy are used for pagetoid spread. Targeted therapy has an emerging role in more complicated cases. For lymph node and distant metastasis, combination treatments should be provided, including lymph node and neck dissection, radiation therapy, systemic chemotherapy, and even orbital exenteration. The rarity of ocular SC precludes a comprehensive perspective on standard treatment. This paper offers a brief review of recent advances in the clinical diagnosis and management of ocular SC based on current scientific literature.

Sebaceous Carcinoma of the Eyelid

BACKGROUND

Periocular sebaceous carcinoma (PSC) is a rare but aggressive neoplasm that tends to clinically and histopathologically mimic other conditions. PSC can be challenging to diagnose using histomorphology alone given its overlap with 2 more common tumors that occur in this area (basal cell carcinoma [BCC] and squamous cell carcinoma [SCC]). Use of immunohistochemistry can help resolve this differential diagnosis.

METHODS

A review of the literature was performed, focusing on the epidemiology, morphology, and immunohistochemical features of PSC.

RESULTS

The most useful immunostains in the differential diagnosis of PSC are epithelial membrane antigen, Ber-Ep4, androgen receptor (AR), and adipophilin. To discern PSC from BCC, one should use EMA, Ber-Ep4, AR, and adipophilin, whereas discerning PSC from SCC can be achieved by evaluating AR and adipophilin. In addition, p53 and ERBB2 (formally known as HER2/neu) are other potentially useful immunohistochemical markers for the differential diagnosis of PSC.

CONCLUSIONS

Use of new immunohistochemical techniques, as well as the elucidation of molecular alterations, such as the presence of ERBB2 amplification, will advance our understanding of PSC.

Concurrent MET copy number gain and KRAS mutation is a poor prognostic factor in pancreatobiliary subtype ampullary cancers

Hepatocyte growth factor (HGF) and MET are candidates of targeted therapies for cancer patients. Although MET and HGF are commonly expressed in biliary tract cancers, their expression and gene copy number status and their association with KRAS mutations have not been investigated in pancreatobiliary-type ampullary adenocarcinomas (A-ACs), one of the aggressive periampullary cancers. MET and HGF expressions and MET copy number status were examined by performing immunohistochemistry (IHC) and silver in situ hybridization (SISH) in 62 surgically resected, paraffin-embedded tumors, respectively. High MET and HGF protein expressions were detected in 24 (38.7%) and 15 (24.2%) tumors. High MET expression was associated with KRAS mutation. However, there were no associations of high MET/HGF expression alone with other clinicopathological feature or survival. MET SISH positivity was detected in 19 tumors (30.6%), where 84.2% were due to high trisomy or polysomy and only 3 cases (15.8%) were MET gene amplification. The overall MET protein overexpression was well correlated with MET SISH positivity. The concurrent MET SISH positivity and KRAS mutation, not each alone, was an independent poor prognostic factor of disease-free survival only in pancreatobiliary subtype of A-ACs, but not in intestinal subtype. Concurrent MET SISH positivity and KRAS mutation may predict a high risk of recurrence in pancreatobiliary subtype of A-ACs, indicating those markers could be potent candidates for a new therapeutic target in this cancer type. MET IHC can be used as a reliable tool screening for MET copy number status in ampullary cancers.

p16 Expression Is Not a Surrogate Marker for High-Risk Human Papillomavirus Infection in Periocular Sebaceous Carcinoma

PURPOSE

To evaluate the role of high-risk human papillomavirus (HR-HPV) infection in periocular sebaceous carcinoma (SC) using multiple methods of detection, and to determine whether p16 overexpression is present and can be used as a surrogate marker for HR-HPV.

DESIGN

Retrospective observational case series with laboratory investigations.

METHODS

Unstained paraffin sections of 35 cases of periocular SC were analyzed with immunohistochemistry for p16 and subjected to polymerase chain reaction (PCR) for HR-HPV. A subset of 18 lesions that were p16-positive was further studied with a novel method of mRNA in situ hybridization (ISH) for the detection of transcriptionally active HR-HPV, an advanced technique with an enhanced sensitivity and specificity.

RESULTS

The clinical findings were in keeping with those of comparable earlier studies. Strong immunohistochemical p16 positivity (meeting the criterion of >70% nuclear and cytoplasmic staining) was present in 29 of 35 cases of periocular SC (82.9%). The selected 18 p16-positive cases tested were negative for HR-HPV using mRNA ISH. PCR yielded unequivocal results with adequate DNA isolated in 24 cases, 23 of which were negative for HR-HPV. One case was positive for HPV type 16, which was found to be a false positive as collaterally determined by mRNA ISH negativity.

CONCLUSION

No evidence was found for HR-HPV as an etiologic agent in the development of periocular SC using multiple modalities to maximize sensitivity and specificity and reduce the limitations of any single test. p16 overexpression is common in periocular SC but unrelated to HR-HPV status. Although p16 may be used as a surrogate marker for HR-HPV status in other tissue sites, this interpretation of p16 positivity is not applicable to periocular SC.

Updates on the Molecular Pathology of Selected Ocular and Ocular Adnexal Tumors: Potential Targets for Future Therapy

Ophthalmic pathologic studies of retinoblastoma first definitively elucidated a genetic etiology for cancer three decades ago. Advances in DNA sequencing, protein expression profiling, and the exploration of epigenetics have since led to categorization of tumors and clinical prognostication based on genetic aberrancy. There are now many neoplasms that are defined by a characteristic genetic signature. In the past several years alone, much has been discovered in regard to the original tumor-suppressor gene initially defined in retinoblastoma as well as in other intraocular tumors such as medulloepithelioma. Our further understanding of ocular adnexal tumors that result in substantial morbidity and mortality, such as sebaceous carcinoma, has also benefited from a genetic approach. In this article, we review the clinicopathologic features of the foregoing three entities--retinoblastoma, medulloepithelioma, and sebaceous carcinoma--in order to highlight discoveries in their underlying abnormal molecular genetic functioning.

Increased gene copy number of HER2 and concordant protein overexpression found in a subset of eyelid sebaceous gland carcinoma indicate HER2 as a potential therapeutic target

PURPOSE

To identify crucial molecular alterations of receptor tyrosine kinases that can be used as potential therapeutic targets for eyelid sebaceous gland carcinoma (SbGC).

METHODS

The expression levels of HER2, EGFR, C-MET, and FGFR1 were determined by immunohistochemistry (IHC). The copy numbers of the HER2, EGFR, C-MET, and FGFR1 genes were assessed by fluorescence in situ hybridization. The IHC and molecular results were correlated with the clinical parameters.

RESULTS

A total of 49 patients with eyelid SbGC were included in this study. HER2, EGFR, C-MET, and FGFR1 protein expression was detected in 8 of 44 (16.3 %), 8 of 45 (17.8 %), 3 of 35 (8.6 %), and 0 of 45 patient samples, respectively. Increased copy numbers of the HER2 gene were found in 5 of 42 patient samples (11.9 %), including two with amplification (4.7 %) and three with polysomy (7.2 %). EGFR amplification was found in 2 of 33 (6.1 %) and FGFR1 amplification in 4 of 33 patient samples (12.1 %; high-level amplification in one and low-level amplification in three). None of the samples examined exhibited C-MET amplification. Gene copy number of the HER2 gene was correlated with its protein expression (p < 0.0001), whereas copy number of EGFR, C-MET, or FGFR1 was not correlated with protein expression. However, samples with EGFR amplification also exhibited a high level of expression of this protein.

CONCLUSIONS

Extra copies of the HER2, EGFR, and FGFR1 genes were identified in a 6-12 % of eyelid SbGCs. A high level of concordant HER2 expression detected by immunohistochemistry can be predictive of a copy number gain of the HER2 gene. Our data suggest that the therapeutic targeting of HER2 might benefit for a subset of patients with periocular SbGCs.

Expression of p16 and p53 in Intraepithelial Periocular Sebaceous Carcinoma

PURPOSE

Identifying intraepithelial sebaceous carcinoma cells in small periocular biopsies can be difficult, particularly in the conjunctiva. The goal of this study was to evaluate p53 and p16 immunohistochemistry as potential markers of intraepithelial sebaceous carcinoma.

PROCEDURES

A total of 25 tumors, including 4 recurrent lesions, were stained for p16 and p53, with intensity scored as negative, weak, moderate or strong.

RESULTS

Expression of p16 was detected in intraepithelial sebaceous carcinoma cells in 24 of the 25 cases (96%), with only 1 case showing weak immunoreactivity. Intraepithelial p53 immunoreactivity was present in 17 of 25 tumors (68%), but was weak in 3 cases. Expression levels remained relatively stable in primary and recurrent tumors, but varied in a few cases between intraepithelial and subepithelial sites.

CONCLUSIONS

Intraepithelial sebaceous carcinomas stained for p53 and p16 demonstrated moderate to strong immunoreactivity in 100% of cases for at least one of these proteins, suggesting that together they are useful markers for determining the extent of tumor spread. Of the two, p16 was immunoreactive in more cases than p53.