Real-world adalimumab survival and discontinuation factors in hidradenitis suppurativa.

BACKGROUND AND OBJECTIVES: Survival analyses can provide valuable insights into effectiveness and safety as perceived by prescribers. Here, we aimed to evaluate adalimumab (ADA) survival and the interruption risk factors in a multicentre cohort of patients with hidradenitis suppurativa (HS). Moreover, we performed a subanalysis considering the periods before and after the onset of the COVID-19 pandemic. METHODS: We conducted a retrospective study including 539 adult patients with HS who received ADA from 1 May 2015 to 31 December 2022. Overall drug survival was analysed using Kaplan-Meier survival curves and compared between the subgroups via stratified log-rank test. Possible predictors for overall drug survival and reasons for discontinuation were assessed using univariate and multivariate Cox regression. RESULTS: Overall, 50.1% were females with a mean age of 43.5 ± 1 years and a mean BMI of 29.5 ± 6.7. At the start of ADA, 95.29% were biologic-naïve and 24.63% had undergone surgical treatment. During follow-up, 9.46% of patients required dose escalation, while 39.92% interrupted ADA. Concomitant therapy was used in 64.89% of cases. A subanalyses comparing pre- and post-pandemic periods revealed a tendency to initiate ADA treatment at a younger age, among patient with higher BMI and at a lower HS stage after COVID-19 pandemic. Interestingly, ADA demonstrated extended survival compared to previous studies, with a median overall drug survival of 56.2 months (95% CI 51.2 to 80.3). The primary causes for discontinuation were inefficacy (51.69%), followed by adverse effects (21.35%). Female sex, longer delay in HS diagnosis, higher baseline IHS4 score and concomitant spondyloarthritis were associated with poorer ADA survival or increased risk of discontinuation. CONCLUSIONS: ADA demonstrated prolonged survival (median 56.2 months). While addition of antibiotics did not have a positive effect on survival rate, basal IHS4 proved useful in predicting ADA survival.

Treatment of extramammary Paget's disease with imiquimod in a real-life setting: a multicenter retrospective analysis in Spain.

BACKGROUND: Topical imiquimod has shown to be an effective treatment for EMPD, although available evidence supporting its use is based on case reports and small series of patients. OBJECTIVES: To investigate the therapeutic outcomes and analyze potential clinico-pathological factors associated with imiquimod response in a large cohort of EMPD patients. METHODS: Retrospective chart review of 125 EMPD patients treated with imiquimod at 20 Spanish tertiary-care hospitals. RESULTS: During the study period, patients received 134 treatment regimens with imiquimod, with 70 (52.2%) cases achieving complete response (CR), 41 (30.6%) partial response and 23 (17.2%) no response. The cumulative CR rates at 24 and 48 weeks of treatment were 46.3% and 71.8%, respectively, without significant differences between first-time and previously treated EMPD. Larger lesions (≥6 cm; p = 0.038) and EMPD affecting >1 anatomical site (p = 0.002) were significantly associated with a worse treatment response. However, the CR rate did not differ significantly by the number of treatment applications (≤4 vs. > 4 times/week; p = 0.112). Among patients who achieved CR, 30 (42.9%) developed local recurrences during a mean follow-up period of 36 months, with an estimated 3 and 5-year recurrence free-survival of 55.7% and 36.4%, respectively. CONCLUSIONS: Imiquimod appears as an effective therapeutic alternative for both first-line and previously treated EMPD lesions. However, a less favorable therapeutic response could be expected in larger lesions and those affecting >1 anatomical site. Based on our results, a 3-4 times weekly regimen of imiquimod with a treatment duration of at least 6 months could be considered an appropriate therapeutic strategy for EMPD patients.

Therapeutic outcomes and survival analysis of Extramammary Paget's disease: A multicentre retrospective study of 249 patients.

BACKGROUND: Evidence regarding long-term therapeutic outcomes and disease-specific survival (DSS) in Extramammary Paget's disease (EMPD) is limited. OBJECTIVES: To assess the DSS and outcomes of surgical and nonsurgical therapeutic modalities in a large cohort of EMPD patients. METHODS: Retrospective chart review of EMPD patients from 20 Spanish tertiary care hospitals. RESULTS: Data on 249 patients with a median follow-up of 60 months were analyzed. The estimated 5-, 10-, and 15-year DSS was 95.9%, 92.9%, and 88.5%, respectively. A significantly lower DSS was observed in patients showing deep dermal invasion (≥1 mm) or metastatic disease (P < .05). A ≥50% reduction in EMPD lesion size was achieved in 100% and 75.3% of patients treated with surgery and topical therapies, respectively. Tumor-free resection margins were obtained in 42.4% of the patients after wide local excision (WLE). The 5-year recurrence-free survival after Mohs micrographic surgery (MMS), WLE with tumor-free margins, WLE with positive margins, radiotherapy, and topical treatments was 63.0%, 51.4%, 20.4%, 30.1%, and 20.8%, respectively. LIMITATIONS: Retrospective design. CONCLUSIONS: EMPD is usually a chronic condition with favorable prognosis. MMS represents the therapeutic alternative with the greatest efficacy for the disease. Recurrence rates in patients with positive margins after WLE are similar to the ones observed in patients treated with topical agents.

Prognostic factors for satellitosis or in-transit metastasis in cutaneous squamous cell carcinoma: A multicentric cohort study.

BACKGROUND: Satellitosis or in-transit metastasis (S-ITM) has clinical outcomes comparable to node-positivity in cutaneous squamous cell carcinoma (cSCC). There is a need to stratify the risk groups. OBJECTIVE: To determine which prognostic factors of S-ITM confer an increased risk of relapse and cSCC-specific-death. METHODS: A retrospective, multicenter cohort study. Patients with cSCC developing S-ITM were included. Multivariate competing risk analysis evaluated which factors were associated with relapse and specific death. RESULTS: Of a total of 111 patients with cSCC and S-ITM, 86 patients were included for analysis. An S-ITM size of ≥20 mm, >5 S-ITM lesions, and a primary tumor deep invasion was associated with an increased cumulative incidence of relapse (subhazard ratio [SHR]: 2.89 [95% CI, 1.44-5.83; P = .003], 2.32 [95% CI, 1.13-4.77; P = .021], and 2.863 [95% CI, 1.25-6.55; P = .013]), respectively. Several >5 S-ITM lesions were also associated with an increased probability of specific death (SHR: 3.48 [95% CI, 1.18-10.2; P = .023]). LIMITATIONS: Retrospective study and heterogeneity of treatments. CONCLUSION: The size and the number of S-ITM lesions confer an increased risk of relapse and the number of S-ITM an increased risk of specific-death in patients with cSCC presenting with S-ITM. These results provide new prognostic information and can be considered in the staging guidelines.

Randomized controlled trial on healthy volunteers of pharmacokinetic and antimicrobial activity of a novel hydrogel-containing chlorhexidine dressing to prevent catheter-related bloodstream infection.

Introduction: Catheter-related blood stream infection (CRBSI) is one of the most relevant complications associated to the use of intravascular catheters. In this context, chlorhexidine gluconate (CHG) releasing dressings have been developed to reduce the catheter colonization rate and the risk of infection. The aim of this study is to analyze the release rate of CHG and the antimicrobial activity of a novel CHG-releasing dressing, Oper film® protect CHG, and to compare these parameters to those of the dressing Tegaderm™ CHG in healthy volunteers. Methods: The study was performed in a cohort of 25 healthy volunteers. Two commercially available chlorhexidine-containing dressings were evaluated and compared in this study, Oper film® protect CHG and Tegaderm™ CHG. The release of CHG and the antimicrobial capacity was determined for one week. Results: HPLC analysis revealed that both dressings have an equivalent CHG release to the skin 2 days (Oper film® protect CHG, 321 µg/cm2; Tegaderm™ CHG, 279 µg/cm2) and 7 days (Oper film® protect CHG, 456 µg/cm2; Tegaderm™ CHG, 381 µg/cm2) after the placement of the products in the non-disinfected back of the subjects. On the other hand, Oper film® protect CHG and Tegaderm™ CHG similarly reduced colony forming units (CFU) in cultures obtained from the skin under the CHG-containing hydrogel compared to control cultures at both 2 days (control, 3.34 log10 cfu/cm2; Oper film® protect CHG, 0.64 log10 cfu/cm2; Tegaderm™ CHG, 0.7 log10 cfu/cm2) and 7 days (control, 3.95 log10 cfu/cm2; Oper film® protect CHG, 0.11 log10 cfu/cm2; Tegaderm™ CHG, 1 log10 cfu/cm2). Discussion: Data confirm that the recent commercially available dressing Oper film® protect CHG maintains the release of CHG and the antimicrobial activity during at least 7 days, and possesses equivalent drug release and antimicrobial action to Tegaderm™ CHG.

A Myxoid Fibrotic Reaction Pattern is Associated with Metastatic Risk in Cutaneous Squamous Cell Carcinoma.

Although desmoplasia has been associated with poor prognoses in cutaneous squamous cell carcinoma, little attention has been paid to the patterns of fibrosis. This study aimed to examine the different stromal fibrotic patterns as markers of metastatic risk. We performed a multicenter retrospective study that included 102 cutaneous squamous cell carcinomas (52 non-metastatic and 50 metastatic carcinomas). Clinical and histopathological data were registered. The fibrotic reaction pattern was classified as mature, intermediate or immature depending on the presence of keloid-like collagen and myxoid stroma. The immature pattern (areas characterized by myxoid changes with no inflammation) was observed in 18 samples and its presence was significantly associated with immunosuppression, budding, desmoplasia, perineural invasion, anatomic level, tumoural depth and metastatic risk in the multivariate analysis. Our findings suggest that the presence of an immature myxoid fibrotic pattern, which can be easily identified by routine hematoxylin-eosin staining, is strongly associated with metastatic risk.

The Polycomb proteins RING1B and EZH2 repress the tumoral pro-inflammatory function in metastasizing primary cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in humans and approximately 5% metastasize, usually to regional lymph nodes. Epigenetic regulation of gene expression may allow tumoral cells to acquire new functions in order to escape from the primary tumor. The aim of this study was to investigate the expression and function of proteins of the Polycomb family of epigenetic regulators in the metastatic process of cSCC. A higher expression of RING1B and EZH2 was detected by immunohistochemistry in a series of primary cSCC tumors that metastasized (MSCCs) when compared with non-metastasizing cSCCs (non-MSCCs). Stable downregulation of RING1B and EZH2 in cSCC cells results in enhanced expression of inflammatory cytokines and activation of the NF-κB signaling pathway. Accordingly, non-MSCCs display higher levels of membranous pS176-inhibitor of NF-kB kinase, and their stroma is enriched in neutrophils and eosinophils when compared with MSCCs. In vitro, hematopoietic cells exhibit a substantial migratory response to supernatants from Polycomb-depleted cSCC cells. Altogether, these data indicate that RING1B and EZH2 repress the innate inflammatory cSCC function and impair tumor immunosurveillance and suggest that patients with high-risk cSCCs could benefit from clinical therapies addressed to harness the immune response.

MOHS micrographic surgery for treating erosive adenoma of the nipple: a case report and review of the literature.

BACKGROUND: Erosive adenoma of the nipple (EAN) is a benign condition that involves major ducts of the nipple. Its clinical presentation may resemble other disorders. Complete removal of the nipple is often suggested because of frequent relapse. However, adverse cosmetic and functional results have prompted clinicians to look for other more conservative options. AIMS: To present a case of EAN successfully treated using Mohs micrographic surgery (MMS) and summarize differential diagnosis and treatment. MATERIALS AND METHODS: A 40-year-old woman with EAN was diagnosed by immunohistochemical markers after clinical suspicion. We have reviewed other cases treated with MMS in the literature. RESULTS: In this patient, lesion size was 0.8 cm and the margin specimen was 1 × 0.9 × 0.2 cm, with EAN as histopathologic diagnosis. No atypia or malignancy was reported. Final esthetic outcome was reached with only one session, under local anesthesia and on an outpatient basis. DISCUSSION: Dermatologic lesions appearing on the nipple's surface should be closely followed. Paget's disease, carcinoma or proliferative lesions like EAN have to be considered, and such conditions require different surgical approaches. Traditional complete removal of the nipple is performed in many cases, but it may result in over-treatment and unfavorable cosmetic outcome. MMS is frequently used in dermatologic surgery to treat malignant lesions with a high cure rate, avoiding excess tissue excision and leading to better patient satisfaction. CONCLUSION: EAN can be successfully treated by minimal resection, especially if early diagnosis is done. MMS offers a better aesthetic outcome than traditional total excision.

Use of biological treatments in patients with hidradenitis suppurativa.

Pilosebaceous unit occlusion and secondary inflammatory perifollicular lympho-histiocytic infiltration seem to be the underlying etiopathogenic mechanisms giving rise to hidradenitis suppurativa (HS). Increased levels of tumor necrosis factor (TNF)-alpha and other cytokines such as interleukins 12 and 23 (IL12/23) and interleukins 10 and 17 have been observed in HS lesional skin. Biological drugs have been reported to be effective for HS, but the level and duration of the response are quite variable. Among anti-TNF drugs, adalimumab and infliximab seem to obtain better results in HS. Adalimumab is the only registered systemic agent for HS and results from multicenter clinical trials demonstrate that 58.9% of patients may achieve clinical response without significant adverse events. Continuous treatment seems to maintain the therapeutic response, but discontinuation of the treatment usually results in a rapid relapse of the disease. Infliximab may also obtain a good response profile with 50% improvement of HS lesions. Treatment with ustekinumab for HS resulted in variable results showing a moderate-to-marked improvement in 82% of patients. Anakinra, a recombinant IL-1 receptor antagonist, has been also been postulated as a potential systemic treatment for HS. A reduction in the disease activity in 67% of patients has been reported. Biological drugs seem to represent an effective therapeutic option for HS, but complete and persistent resolution of the disease is rarely achieved. Flares of the disease usually develop regardless the prescribed treatment. Combined treatments including antibiotics and retinoids seem to be a potential additional therapeutic approach. In chronic and severe cases, a surgical approach is mandatory in order to remove persistent scarring tissue. New drugs are currently being evaluated as new insights in the pathogenesis of the disease are elucidated. Several clinical trials with apremilast, anti-IL17 drugs and anti-interleukin-1 alpha are currently ongoing.

Role of Human Papillomavirus in Penile Carcinomas Worldwide.

BACKGROUND: Invasive penile cancer is a rare disease with an approximately 22 000 cases per year. The incidence is higher in less developed countries, where penile cancer can account for up to 10% of cancers among men in some parts of Africa, South America, and Asia. OBJECTIVE: To describe the human papillomavirus (HPV) DNA prevalence, HPV type distribution, and detection of markers of viral activity (ie, E6*I mRNA and p16(INK4a)) in a series of invasive penile cancers and penile high-grade squamous intraepithelial lesions (HGSILs) from 25 countries. A total of 85 penile HGSILs and 1010 penile invasive cancers diagnosed from 1983 to 2011 were included. DESIGN, SETTING, AND PARTICIPANTS: After histopathologic evaluation of formalin-fixed paraffin-embedded samples, HPV DNA detection and genotyping were performed using the SPF-10/DEIA/LiPA25 system, v.1 (Laboratory Biomedical Products, Rijswijk, The Netherlands). HPV DNA-positive cases were additionally tested for oncogene E6*I mRNA and all cases for p16(INK4a) expression, a surrogate marker of oncogenic HPV activity. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: HPV DNA prevalence and type distributions were estimated. RESULTS AND LIMITATIONS: HPV DNA was detected in 33.1% of penile cancers (95% confidence interval [CI], 30.2-36.1) and in 87.1% of HGSILs (95% CI, 78.0-93.4). The warty-basaloid histologic subtype showed the highest HPV DNA prevalence. Among cancers, statistically significant differences in prevalence were observed only by geographic region and not by period or by age at diagnosis. HPV16 was the most frequent HPV type detected in both HPV-positive cancers (68.7%) and HGSILs (79.6%). HPV6 was the second most common type in invasive cancers (3.7%). The p16(INK4a) upregulation and mRNA detection in addition to HPV DNA positivity were observed in 69.3% of HGSILs, and at least one of these HPV activity markers was detected in 85.3% of cases. In penile cancers, these figures were 22.0% and 27.1%, respectively. CONCLUSIONS: About a third to a fourth of penile cancers were related to HPV when considering HPV DNA detection alone or adding an HPV activity marker, respectively. The observed HPV type distribution reinforces the potential benefit of current and new HPV vaccines in the reduction of HPV-related penile neoplastic lesions. PATIENT SUMMARY: About one-third to one-quarter of penile cancers were related to human papillomavirus (HPV). The observed HPV type distribution reinforces the potential benefit of current and new HPV vaccines to prevent HPV-related penile neoplastic lesions.

Identification of somatic gene mutations in penile squamous cell carcinoma.

There is a lack of studies on somatic gene mutations and cell signaling driving penile carcinogenesis. Our objective was to analyze somatic mutations in genes downstream of EGFR in penile squamous cell carcinomas, especially the mTOR and RAS/MAPK pathways. We retrospectively analyzed somatic mutations in 10 in situ and 65 invasive penile squamous cell carcinomas by using Sequenom's Mass Spectrometry iPlex Technology and Oncocarta v1.0 Panel. The DNA was extracted from FFPE blocks and we identified somatic missense mutations in three in situ tumors and in 19 invasive tumors, mostly in PIK3CA, KRAS, HRAS, NRAS, and PDGFA genes. Somatic mutations in the PIK3CA gene or RAS family genes were neither associated with tumor grade, stage or outcome, and were equally often identified in hrHPV positive and in hrHPV negative tumors that showed no p53 expression. Mutations in PIK3CA, KRAS, and HRAS are frequent in penile squamous cell carcinoma and likely play a role in the development of p53-negative tumors. Although the presence of these mutations does not seem to correlate with tumoral behavior or outcome, they could be biomarkers of treatment failure with anti-EGFR mAb in patients with penile squamous cell carcinoma.

Active nuclear IKK correlates with metastatic risk in cutaneous squamous cell carcinoma.

About 5% of all cutaneous squamous cell carcinomas (cSCCs) metastasize, which is the principal cause of death by this type of cancer. However, to date there are no reliable biomarkers that categorize those SCC patients that will progress to metastasis. Nuclear active IKKα diminishes Maspin levels in prostate cancer facilitating its metastatic potential. In this paper, we describe the immunohistochemical analysis of active IKK and Maspin in 56 metastasizing and 51 non-metastasizing primary cSCC to measure their association with cancer behaviour. We also determined the effect of inhibiting IKK activity in SCC cell growth and migration in vitro. We found that high levels of nuclear active IKK in the primary tumour are predictive of cSCC metastatic capacity, in particular when combined with poor tumour differentiation and a history of tumour recurrence. Active IKK inversely correlated with Maspin levels in cSCC tumours, and samples negative for Maspin are exclusively found in the metastatic group. Mechanistically, IKK activity regulates cellular motility and SCC cell survival. Our results indicate that nuclear active IKK is a robust biomarker to predict cSCC outcome, and suggest the possibility of targeting IKK activity as a future therapy for treating metastatic cSCC.

Epithelial-to-mesenchymal transition in penile squamous cell carcinoma.

PURPOSE: Epithelial-to-mesenchymal transition is a phenomenon in epithelial tumors that involves loss of intercellular adhesion, mesenchymal phenotype acquisition and enhanced migratory potential. While the epithelial-to-mesenchymal transition process has been extensively linked to metastatic progression of squamous cell carcinoma, studies of the role of epithelial-to-mesenchymal transition in squamous cell carcinoma containing high risk human papillomaviruses are scarce. Moreover, to our knowledge epithelial-to-mesenchymal transition involvement in human penile squamous cell carcinoma, which can arise through transforming HPV infections or independently of HPV, has not been investigated. We evaluated the presence of epithelial-to-mesenchymal transition markers and their relationship to HPV in penile squamous cell carcinoma. MATERIALS AND METHODS: We assessed the expression of E-cadherin, vimentin and the epithelial-to-mesenchymal transition related transcription factors Twist, Zeb1 and Snail by immunohistochemical staining in 64 penile squamous cell carcinoma cases. HPV was detected by polymerase chain reaction amplification. RESULTS: Simultaneous loss of membranous E-cadherin expression and vimentin over expression were noted in 43.5% of penile squamous cell carcinoma cases. HPV was significantly associated with loss of membranous E-cadherin but not with epithelial-to-mesenchymal transition. Recurrence and mortality rates were significantly higher in cases showing epithelial-to-mesenchymal transition. CONCLUSIONS: Our findings indicate that in penile squamous cell carcinoma epithelial-to-mesenchymal transition is associated with poor prognosis but not with the presence of HPV.

Epithelial to mesenchymal transition markers are associated with an increased metastatic risk in primary cutaneous squamous cell carcinomas but are attenuated in lymph node metastases.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in humans and approximately 5% metastasize, usually to regional lymph nodes. Epithelial to mesenchymal transition (EMT) is a process involving loss of intercellular adhesion, acquisition of a mesenchymal phenotype and enhanced migratory potential; epithelial markers, such as E-cadherin, are down-regulated and mesenchymal proteins (Vimentin), increased. OBJECTIVE: To investigate the expression of EMT markers in metastatic SCC (MSCC) and their corresponding metastases, and to correlate them with clinico-pathological factors associated with an increased risk of metastasis. METHODS: We performed a retrospective study that included 146 cSCC samples (51 primary non-metastatic, 56 primary metastatic, 39 lymphatic metastases). Immunohistochemistry for E-cadherin, Vimentin, Snail, beta-catenin, Twist, Zeb1 and Podoplanin was performed. RESULTS: Loss of membranous E-cadherin was observed in 77% cSCCs, with no differences between MSCC and non-MSCC. Among the transcriptional factors controlling EMT, no significant Snail1 expression was detected. Twist, Zeb1, Vimentin, beta-catenin and Podoplanin were significantly overexpressed in MSCCs. Twist ectopic expression in SCC13 cells induced Zeb1, Vimentin and Podoplanin expression and E-cadherin delocalization. These changes resulted in a scattered migration pattern in vitro. Expression of EMT markers was decreased in the metastases when compared with the corresponding primary tumors. CONCLUSION: These results suggest that a partial EMT, characterized by the expression of Twist but without a total E-cadherin depletion, is involved in the acquisition of invasive traits by cSCC, but the process is downregulated in lymph node metastases.

mTOR signaling pathway in penile squamous cell carcinoma: pmTOR and peIF4E over expression correlate with aggressive tumor behavior.

PURPOSE: Penile squamous cell carcinoma is a rare neoplasm associated with a high risk of metastasis and morbidity. There are limited data on the role of the mTOR signaling pathway in penile squamous cell carcinoma carcinogenesis and tumor maintenance. We assessed a possible role for mTOR signaling pathway activation as a potential predictive biomarker of outcome and a therapeutic target for penile cancer. MATERIAL AND METHODS: A cohort of 67 patients diagnosed with invasive penile squamous cell carcinoma from 1987 to 2010 who had known HPV status were selected for study. Tissue microarrays were constructed with 67 primary penile squamous cell carcinomas, matched normal tissues and 8 lymph node metastases. Immunohistochemical staining was performed for p53, pmTOR, pERK, p4E-BP1, eIF4E and peIF4E. Expression was evaluated using a semiquantitative H-score on a scale of 0 to 300. RESULTS: Expression of pmTOR, p4E-BP1, eIF4E and peIF4E was increased in penile tumors compared with matched adjacent normal tissues, indicating activation of the mTOR signaling pathway in penile tumorigenesis. Over expression of pmTOR, peIF4E and p53 was significantly associated with lymph node disease. peIF4E and p53 also correlated with a poor outcome, including recurrence, metastasis or disease specific death. In contrast, pERK and p4E-BP1 were associated with lower pT stages. pmTOR and intense p53 expression was associated with HPV negative tumors. CONCLUSIONS: Activation of mTOR signaling may contribute to penile squamous cell carcinoma progression and aggressive behavior. Targeting mTOR or its downstream signaling targets, such as peIF4E, may be a valid therapeutic strategy.

Identification and genotyping of human papillomavirus in a Spanish cohort of penile squamous cell carcinomas: correlation with pathologic subtypes, p16(INK4a) expression, and prognosis.

BACKGROUND: Penile squamous cell carcinoma (PSCC) is a tumor with a high metastatic potential. In PSCC the attributable fraction to human papillomavirus (HPV) is not well established. OBJECTIVE: We sought to provide novel data about the prevalence of HPV in a large series of penile intraepithelial neoplasia (PeIN) and invasive PSCC, correlating the results with the histologic subtype, p16(INK4a) immunostaining, and prognosis. METHODS: A total of 82 PSCC were included in the study, 69 invasive and 13 PeIN. HPV detection was performed by polymerase chain reaction with SPF-10 broad-spectrum primers followed by DNA enzyme immunoassay and genotyping with a reverse hybridization line probe assay. P16(INK4a) immunohistochemical expression on tissue microarrays was also analyzed. RESULTS: HPV DNA was identified in 31 of 77 (40.2%) PSCC (22 of 67 invasive and 9 of 10 PeIN). In 25 of 31 (80.6%) cases HPV-16 was identified. HPV detection was significantly associated with some histologic subtypes: most basaloid and warty tumors were high-risk HPV (hrHPV) positive, whereas only 15% of usual PSCC were hr-HPV positive. All hrHPV-positive PSCC had an adjacent undifferentiated PeIN. Strong p16(INK4a) immunostaining correlated with hrHPV infection. Most undifferentiated PeIN showed p16(INK4a) immunohistochemical overexpression. Both hrHPV-positive and p16(INK4a)-positive tumors showed a better overall survival without reaching statistical significance. LIMITATIONS: This was a retrospective study. CONCLUSIONS: Our results suggest that most hrHPV-positive PSCC develop from undifferentiated hrHPV-positive PeIN. P16(INK4a) immunostaining may be useful in identifying both etiologically related hrHPV-positive tumors and those with better outcome. The routine use of p16(INK4a) staining should be incorporated in histologic evaluation of PSCC.