Immunohistochemical Patterns Research Articles

Tumor risk markers in recurrent respiratory papillomatosis.

This study aims to investigate the pattern of immunoexpression of proteins p16, p53 and Ki-67 in RRP, as well as to evaluate its influence on the number of surgeries that patients have undergone to date and to analyze the benefit of immunohistochemistry in this disease. Clinical-demographic data and tumor samples were obtained from 33 patients with RRP. The expression of proteins p16, p53 and Ki-67 was analyzed by immunohistochemical method. Most patients had already undergone more than one surgery. The p16 marker was negative in 24.2% of the cases, with little positivity in 27.3% of the cases, moderate in 36.4% and intense in 12.1%. The p53 marker was positive in all cases, with little immunoexpression in 39.4% of cases, moderate in 36.4% and intense in 24.2%. The Ki-67 marker showed nuclear positivity in all lesions, although in varying degrees, with a mean proliferative index ± SD (standard deviation) of 51.7 ± 26. The papillomatous lesions had varying degrees of immunoexpression of proteins p16, p53 and Ki-67, but no specific immunohistochemical pattern was observed. It was found, with statistical difference, that the number of surgeries was higher in cases with greater intensity of p53 expression, without correlation with the other markers. The benefit of immunohistochemistry in recurrent respiratory papillomatosis may lie in the prognostic assessment. However, further studies are needed to evaluate the use of this technique for this purpose. 4.

Differentiating fulminant EBV infection complicated by HLH from Lymphoma: report of a case and a brief literature review

Epstein-Barr virus (EBV) infection may present with fulminant constitutional symptoms, cytopenia(s), and systemic lymphadenopathy, raising clinical suspicion for lymphoma and prompting lymph node and bone marrow biopsies. At the microscopic level, the histopathologic findings in cases of acute EBV lymphadenitis may mimic certain lymphoid neoplasms, creating a range of differential diagnoses and diagnostic pitfalls.We present a case of fulminant EBV infection in an adolescent whose clinical and radiographic findings led to lymph node and bone marrow biopsies to rule out lymphoma. One week after being diagnosed with acute EBV infection (infectious mononucleosis), a 17-year-old Caucasian male presented with worsening symptoms including persistent fever, progressive, painful lymphadenopathy, and splenomegaly. A peripheral blood smear showed lymphocytosis with many reactive lymphocytes, anemia, and thrombocytopenia. Laboratory studies showed elevated ferritin, triglycerides, and soluble IL-2/CD25. A cervical lymph node biopsy demonstrated an EBV-positive, reactive B-immunoblast proliferation with large atypical lymphoid cells mimicking Reed-Sternberg cells of Hodgkin lymphoma, in addition to patchy vasculitis, coagulative necrosis, and prominent hemophagocytic activity. Bilateral bone marrow biopsies showed a hypercellular marrow with patchy infiltrates of similar EBV-positive, large atypical lymphoid cells, as well as prominent hemophagocytic activity. The diagnosis of acute EBV associated lymphoproliferation with concurrent hemophagocytic lymphohistiocytosis (HLH) was rendered.Recognition of common and uncommon clinical presentations of acute EBV infection is essential, particularly when histopathologic findings raise suspicion for a possible hematolymphoid neoplasm. Both the lymph node architectural and viral cytopathic changes observed in EBV lymphadenitis exhibit significant morphologic overlap with classic Hodgkin lymphoma (cHL) and several other lymphomas, including anaplastic large cell lymphoma, diffuse large B cell lymphoma, and angioimmunoblastic T cell lymphoma. Recognition of immunohistochemical staining patterns in EBV lymphadenitis is critical to avoid misdiagnosis. Conversely, bona fide lymphoma, particularly cHL, can masquerade as EBV infection. We provide a concise discussion and tables of the histopathologic differential diagnosis of EBV lymphadenitis, including cHL and other lymphomas. Pathologists should include acute EBV infection within the differential diagnosis when confronted with clinical and pathologic findings concerning for lymphoma, particularly in adolescents and young adults.

Classification of Vulvar Squamous Cell Carcinoma and Precursor Lesions by p16 and p53 Immunohistochemistry: Considerations, Caveats, and an Algorithmic Approach

There is emerging evidence that vulvar squamous cell carcinoma (VSCC) can be prognostically subclassified into 3 groups based on human papillomavirus (HPV) and p53 status: HPV-associated (HPV+), HPV-independent/p53 wild-type (HPV−/p53wt), or HPV-independent/p53 abnormal (HPV−/p53abn). Our goal was to assess the feasibility of separating VSCC and its precursors into these 3 groups using p16 and p53 immunohistochemistry (IHC). A tissue microarray containing 225 VSCC, 43 usual vulvar intraepithelial neoplasia (uVIN/HSIL), 10 verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN), and 34 differentiated VIN (dVIN), was stained for p16 and p53. Noncomplementary p16 and p53 patterns were resolved by repeating p53 IHC and HPV RNA in situ hybridization (ISH) on whole sections, and sequencing for TP53. Of 82 p16-positive VSCC, 73 (89%) had complementary p16 and p53 patterns and were classified into the HPV+ group, 4 (4.9%) had wild-type p53 staining, positive HPV ISH and were classified into the HPV+ group, whereas 5 (6.1%) had p53 abnormal IHC patterns (1 null, 4 overexpression), negativity for HPV ISH, and harbored TP53 mutations (1 splice site, 4 missense); they were classified as HPV−/p53abn. Of 143 p16-negative VSCC, 142 (99.3%) had complementary p53 and p16 patterns: 115 (80.4%) HPV−/p53abn and 27 (18.9%) HPV−/p53wt. One had a basal-sparing p53 pattern, positivity for HPV ISH and was negative for TP53 mutations—HPV+ category. The use of IHC also led to revised diagnoses—HSIL to dVIN (3/43), dVIN to vaVIN (8/34), and dVIN to HSIL (3/34). Overall, 215/225 VSCC (95.6%) could be easily classifiable into 3 groups with p16 and p53 IHC. We identified several caveats, with the major caveat being that “double-positive” p16/p53 should be classified as HPV−/p53abn. We propose an algorithm that will facilitate the application of p16 and p53 IHC to classify VSCC in pathology practice.

Gross, Histologic and Immunohistochemical Characteristics of Keratoacanthomas in Lizards.

The present study describes the clinical behavior as well as the histopathologic and immunohistochemical characteristics of keratoacanthomas (Kas) in three different saurian species. While Kas presented as two dermal lesions in a bearded dragon (Pogona vitticeps), multicentric Kas were observed in three panther chameleons (Furcifer pardalis) and a veiled chameleon (Chamaeleo calyptratus). Macroscopically, Kas presented as dome-shaped skin tumors with a centralized keratinous pearl and a diameter ranging from 0.1-1.5 cm. In all lizards, Kas were predominantly located at the dorsolateral body wall, and KA of the eyelid was additionally observed in three out of four chameleons. Histologically, KAs presented as relatively well-defined, circumscribed epidermal proliferations that consisted of a crateriform lesion containing a central keratinous pearl with minimally infiltrating borders. In all KAs, a consistent immunohistochemical pattern was observed, with the expression of cyclooxygenase-2, E-cadherin, and pan-cytokeratin. A follow-up period of one to two years was established in all lizards. While no recurrence was observed in the panther chameleons, recurrence of a single keratoacanthoma was observed in the bearded dragon after one year, and in the veiled chameleon, multicentric keratoacanthomas reappeared during a follow-up period of two years. We describe KA as a previously unrecognized neoplastic entity in lizards that constitutes a low-grade, non-invasive but rapidly growing skin tumor that may show a multicentric appearance, especially in chameleons. As previously postulated for dermal squamous cell carcinomas (SCC), artificial ultraviolet lighting may play an important role in the oncogenesis of KAs in lizards. Although dermal SCCs in lizards show similar predilection sites and gross pathologic features, our results suggest that KA should be considered as a histologic variant of SCC that represents a rather benign squamous proliferation in comparison to conventional SCCs. Early diagnosis of KA and reliable discrimination from SCCs are essential for the prognosis of this neoplastic entity in lizards.

Odontogenic-like neoplasms of the rabbit cheek: pathological features and comparison to cutaneous trichoblastoma and jaw-associated ameloblastoma.

Odontogenic neoplasms demonstrate unique histopathological features and are thought to arise from the germinal tissues of the developing tooth germ, effectively restricting their anatomic origin to the tooth-bearing regions of the jaw and directly associated soft tissues of the oral cavity. Ectopic odontogenic-like neoplasms located in the skin of cats, rabbits, and human beings challenge these assumptions. Here we describe the clinical, pathological, and immunohistochemical features of 6 spontaneously occurring odontogenic-like neoplasms arising in the cutaneous tissue of the cheek in client-owned pet rabbits, including ameloblastoma-like (n = 3), ameloblastic fibroma-like (n = 2), and ameloblastic carcinoma-like neoplasms (n = 1). Microscopically, all the cheek tumors featured neoplastic epithelium exhibiting odontogenic architectural structures (plexiform ribbons, anastomosing trabeculae, follicles, cysts, and irregular structures with rounded botryoid protuberances) and 1 or more cardinal odontogenic epithelial features (basal palisading, antibasilar nuclei, and central stellate reticulum-like cells). The pancytokeratin, cytokeratin 5/6, cytokeratin 14, and vimentin immunohistochemical patterns of these odontogenic-like lesions were most similar to those of jaw-associated ameloblastoma and differed from those of cutaneous trichoblastoma. All neoplasms were narrowly excised, and for lesions with clinical follow-up information, none had evidence of recurrence 1-7 months after surgical removal. Although evidence suggests that these odontogenic-like tumors of the rabbit cheek may be derived from ectopic rests of transformed tooth germ, the histogenesis of these lesions remains unresolved.

Expression of E4 Protein and HPV Major Capsid Protein (L1) as A Novel Combination in Squamous Intraepithelial Lesions.

We aim to describe the relationship between the immunohistochemical expression patterns of HPV E4 markers and the presence of HPV major capsid protein (L1) in cervical tissues obtained by biopsy of patients with abnormal liquid-based cytology (LBC) results, HR HPV infections, or clinically suspicious cervix. A novel HPV-encoded marker, SILgrade-E4 (XR-E4-1), and an HPV (clone K1H8) antibody were used to demonstrate the expression in terminally differentiated epithelial cells with a productive HPV infection in the material. A semiquantitative analysis was performed based on light microscope images. The level of E4 protein decreased with the disease severity. Patients with LSIL-CIN 1 and HSIL-CIN 2 diagnoses had significantly lower levels of HPV major capsid protein (L1) than those without confirmed cervical lesions. Our analysis confirms a higher incidence of L1 in patients with molecularly diagnosed HPV infections and excluded lesions of LSIL-CIN 1 and HSIL-CIN 2. Further studies on the novel biomarkers might help assess the chances of the remission of lesions such as LSIL-CIN 1 and HSIL-CIN 2. Higher levels of E4 protein and L1 may confirm a greater probability of the remission of lesions and incidental infections. In the cytological verification or HPV-dependent screening model, testing for E4 protein and L1 expression may indicate a group with a lower risk of progression of histopathologically diagnosed lesions.

Concentric Centrifugal Figurate Erythema as an Unusual COVID-19 Evanescent Skin Manifestation in a Patient With CD3+/CD45+ Lymphocyte Infiltration: A Case Report

Introduction: Coronavirus disease 2019 (COVID-19) may be associated with various skin manifestations. Among them, figurate erythema (FE) is rare; only a few clinical reports have been published. Herein, we reported an unusual concentric FE lesions and their immunohistochemical profile in a patient with COVID-19. Case presentation: A 52-year-old woman was diagnosed with COVID-19. One month later, she developed asymptomatic annular erythematous concentric ring lesions on her inner right thigh. The margin of every ring increased in coloration, and the lesions then completely resolved in 2 weeks. A biopsy revealed vasculitis of small vessels, an increase in the fluorescence intensity of CD3 and CD45, and negativity for COVID-19 RNA. Discussion: The results showed an unusual FE that has a clinical mixed type between erythema annulare centrifugum and erythema gyratum repens; the physiopathological mechanism in the FE due to COVID-19 is unknown; one theory involves rapid viral passage into the cutaneous vascular system that triggers an immune and inflammatory response. Although the results exhibited a negative COVID-19 RNA in the tissue, the CD3+/CD45+ lymphocyte infiltration could explain the clinical pattern as a direct inflammatory response in the small vessel or as a delayed immune response. Conclusion: Our findings suggest an immunohistochemical small vessel vasculitis pattern with an unusual clinical FE that differs from other types of COVID-19–associated FE or erythema reported previously.

P53-Abnormal “Fields of Dysplasia” in Human Papillomavirus–Independent Vulvar Squamous Cell Carcinoma Impacts Margins and Recurrence Risk

Abnormal p53 (p53abn) immunohistochemical (IHC) staining patterns can be found in vulvar squamous cell carcinoma (VSCC) and differentiated vulvar intraepithelial neoplasia (dVIN). They can also be found in the adjacent skin that shows morphology that falls short of the traditional diagnostic threshold for dVIN. Vulvectomy specimens containing human papillomavirus–independent p53abn VSCC with margins originally reported as negative for invasive and in situ disease were identified. Sections showing the closest approach by invasive or in situ neoplasia to margins were stained with p53 IHC stains. We evaluated the following: (1) detection of morphologically occult p53abn in situ neoplasia, (2) rates of margin status change after p53 IHC staining, and (3) effect of p53abn IHC staining at margins on the 2-year local recurrence rates. Seventy-three human papillomavirus–independent p53abn VSCCs were included. Half (35/73, 48%) had documented an in situ lesion in the original report. The use of p53 IHC staining identified 21 additional cases (29%) with the p53abn in situ lesions that were originally unrecognized. The histology of in situ lesions in the p53abn “field” varied and became more subtle (morphologically occult) farther away from the VSCC. Fifteen (21%) cases had a morphologically occult and previously unrecognized p53abn in situ lesion present at a resection margin, which conferred an increased risk of local recurrence (5/7 [71.4%] vs 6/22 [27.3%], P = .036). The p53abn in situ lesions at a margin were confirmed to have TP53 mutations by sequencing. p53 IHC staining identified morphologically occult p53abn in situ lesions surrounding human papillomavirus–independent VSCC. p53abn IHC staining at a margin was associated with a 3-fold increased risk of local recurrence.

Mass Spectrometry Proteomic Analysis of Four p53 Patterns in Differentiated Vulvar Intraepithelial Neoplasia.

The histopathologic diagnostic criteria of differentiated vulvar intraepithelial neoplasia (dVIN), the precursor of human papillomavirus-independent squamous cell carcinoma, are basal atypia, a negative or non-block-positive p16, and a supportive p53 immunohistochemistry (IHC). Several different patterns of supportive p53 IHC have been described. This study aims to determine the relationship between p53 IHC patterns and mass spectrometry analysis of cellular proteins in dVIN. Four patterns of p53 IHC were studied: overexpression, cytoplasmic, wild type, and intermediate expression between wild type and overexpression. For each pattern, tissue samples of 4 examples were subjected to mass spectrometry. The protein profile within each p53 IHC pattern shared common features. Each of the 4 p53 patterns had a distinguishable protein profile when compared with the other 3 patterns. The distinguishable protein profiles in different p53 IHC patterns suggest diverse mechanisms of TP53 dysfunction. Subtyping dVIN by p53 IHC is worthy of further study because varied protein expression profiles may translate into different clinical behavior.

Immune-cell infiltration in high-grade soft tissue sarcomas; prognostic implications of tumor-associated macrophages and B-cells

Background Soft tissue sarcomas are rare, morphologically, and genetically heterogenous. Though the tumors display abundant tumor stroma with infiltrating immune cells, the prognostic impact of various immunologic markers in sarcoma remains poorly defined. We aimed to characterize the immune landscape of a treatment-naïve cohort of soft tissue sarcoma of the extremities and the trunk wall with correlations to metastasis-free survival. Materials and Methods We surveyed immunohistochemical expression patterns for CD163, CD20, CD3, CD8, and FOXP3 in 134 adult high-grade leiomyosarcomas, liposarcomas, and synovial sarcomas. Results Macrophages outnumbered tumor-infiltrating lymphocytes. High CD163 infiltration was identified in 49% of the tumors and was overrepresented (66%) in leiomyosarcoma compared to liposarcoma (46%) and synovial sarcoma (9%). Tumor-grade also correlated with CD163 positivity with high expression in 53% of the high-grade lesions and 28% in low-grade tumors. Infiltrating CD3, CD8 and FOXP3-positive T-cells were significantly more prevalent in leiomyosarcomas than in liposarcomas/synovial sarcomas. CD20+ B-cells were identified only in 14% of the STS. Correlation to established prognostic factors revealed a correlation between CD163+ macrophages and necrosis and predicted an increased risk of metastases. No correlation between CD20+ B-cells and known prognostic factors could be established, though CD20+ B-cells infiltration predicted improved overall survival. Conclusion We confirm that tumor-infiltrating macrophages outnumber tumor-infiltrating lymphocytes in soft tissue sarcoma and signify an increased risk of metastasis. CD20+ B-cells are scarce in STS and correlate to improved survival. To date, immunotherapeutic strategies directed against T-cells have shown limited effect in soft tissue sarcoma. Our observations suggest that immunomodulatory agents focusing on macrophages may be worthwhile for further investigations in this tumor type. Further studies exploring the prognostic and predictive significance of CD20+ B cells are warranted.

Immunohistochemical Expression of E-cadherin in Premalignant and Malignant Squamous Lesions of the Oral Cavity: A Cross-sectional Study

Introduction: Squamous Cell Carcinoma (SCC) constitutes 90% of the malignancies of the oral cavity, making it the 6th most common cancer worldwide. Premalignant lesions of the oral cavity carry an increased risk for the development of oral SCC, which is a multistage process. Numerous molecules are involved in this process, and E-cadherin is one of them. E-cadherin is a 120 kDa glycoprotein and a calcium-dependent molecule involved in cell adhesion. Altered expression of E-cadherin has been described in preinvasive lesions and malignancies of the cervix, oesophagus, and head and neck. Aim: The aim of this study was to observe the immunohistochemical (IHC) expression pattern of E-cadherin in premalignant and malignant lesions of the oral cavity and to correlate E-cadherin immunoexpression between different grades of dysplasia and malignancy. Materials and Methods: This cross-sectional, ambispective study was conducted at Sri Dharmasthala Manjunatheshwara College of Medical Sciences and Hospital, Dharwad, Karnataka, India. The study duration was two and a half years, with one year being retrospective from July 2014 to June 2015, and the remaining period being prospective from July 2015 to December 2016. Systematic random sampling was done to select 60 cases. Premalignant and malignant lesions of the oral squamous epithelium were classified according to the 2017 World Health Organization (WHO) classification and subjected to E-cadherin immunohistochemistry. Grading of expression was based on the percentage of cells showing continuous homogenous membranous staining: 0 (negative)=0 to 10%, 1+ (loss)=11-25%, 2+ (weak)=26% to 50%, 3+ (strong)=51% to 75%, 4+ (intense)=>75% of cells. Results were analysed using the Statistical Package for Social Sciences version 20.0. Results: The expression of E-cadherin between the different grades of premalignant lesions varied significantly (p-value=0.003), ranging from intense expression in mild dysplasia to weak expression in high grades of dysplasia. Immunoexpression was intense (4+) in 50% of cases, strong (3+) in 39.28%, and weak (2+) in 7.14% of cases. The expression of E-cadherin between the different grades of malignant lesions also varied significantly (p-value=0.002), ranging from negative expression in poorly differentiated SCC to strong expression in well-differentiated SCC. Immunoexpression was negative (0) in 31.25% of cases, strong (3+) in 31.25%, weak (2+) in 15.62%, and (1+) in 21.87% of cases. The pattern of expression was also significant between premalignant and malignant lesions (p-value<0.0001). Conclusion: As the grades of dysplasia and malignancy increase, the expression of E-cadherin reduces. Hence, there is a negative correlation between E-cadherin expression and the grades of dysplasia and malignancy.

Can CXCL13 be a prognostic marker in clear cell renal cell carcinoma?

CXCL13, B-lymphocyte chemoattractant, has been associated with many diseases and cancers. One of the malignancies that CXCL13 has been investigated is clear cell renal cell carcinomas which are the most common subtype of renal cancers. The aim of this study is to evaluate the immunohistochemical staining patterns of CXCL13 in clear cell renal cell carcinomas and to determine its relationship with pathological tumor stage, risk factors, and prognostic parameters. In this study, 99 patients who underwent partial/radical nephrectomy diagnosed with clear cell renal cell carcinoma were included. Four micron sections were taken from paraffin embedded blocks containing sufficient tumor and kidney tissue. Samples were immunohistochemically stained with CXCL13 antibody. During microscopic examination, CXCL13 positive stained cells in ten high magnification fields were counted and evaluated using a semiquantitative H score: 3 × strongly stained + 2 × moderately stained + 1 × weakly stained. The cut-off value was set as 40 for values between 0 and 300. The low and high stained groups were compared with prognostic parameters and risk factors. The difference of continuous variables between the two groups was examined with the t test and the distribution of categorical variables with the Chi-square test. A value of P < 0.05 was considered to be statistically significant. The number of lymphocytes stained with CXCL13 in the tumor was higher than in the normal kidney parenchyma (p = 0.07). Intratumoral lymphocytes were highly stained with CXCL13 in 57.5% of pT3 cases and 31.7% of pT1 cases. The amount of intratumoral lymphocytes stained with CXCL13 increased in advanced pathological stages (p = 0.05). Nonsmoking cases were mostly in the low staining group (p = 0.06). The relationship we found between advanced pathological stage and intratumoral CXCL13 staining in our study suggests that CXCL13 has a prognostic value in this cancer.

A Case of Laryngeal Granular Cell Tumor

Granular cell tumors can occur at any body site. While in about a half of the cases, they arise in the head and neck region, occurrence in the larynx is rare. Based on their characteristic immunohistochemical staining patterns, granular cell tumors are thought to arise from Schwann cells. In all but a small percentage of cases, the tumors are benign. Multiple tumors in the body are seen in 10%-14% of cases. Herein, we report a case of granular cell tumor of the vocal cord.

Immunohistochemical Evaluation of p16 and p53 in Oral and Oropharyngeal Squamous Cell Carcinoma with Special Regard to Human Papillomavirus Status.

Incidence of human papillomavirus (HPV)-associated oral and oropharyngeal squamous cell carcinomas (OSCC and OPSCC) is on a rising trend globally and has specific therapeutic implications. HPV-related tumors have a distinct pathogenetic mechanism targeting p16 and p53 both. However, there are limited studies evaluating p16 and p53 expression in combination. The aim of the study is to evaluate p16 and p53 immunohistochemical expression pattern in OSCC and OPSCC, with special reference to HPV association. This was a hospital-based prospective study done over 22 months (September 2018 to June 2020), including a total of 54 cases of OSCC and OPSCC. They were subjected to clinicopathological evaluation, p16 and p53 immunohistochemistry, and DNA polymerase chain reaction testing for testing of HPV association, followed by analysis of data by statistical methods. Out of 54, 43 cases were OSCC and 11 cases were OPSCC. A total of nine cases were HPV positive. HPV association was found to be significant with tonsil as primary site, age range between 40 and 60 years, and absence of tobacco or alcohol habit. Presence of HPV infection was also significantly associated with p16 overexpression, in combination with p53 negativity. The findings indicate that p16 overexpression combined with a negative p53 expression can be used for HPV detection and the former alone may be used as diagnostic marker in OPSCC only. HPV-associated OSCC and OPSCC are a unique subset of cancers, and using combination of molecular biomarkers could help in diagnosis and prognosis.

Immunohistochemical Expression of p16 and p53 as Prognostic Indicator in Oral Squamous Cell Carcinoma: A Cross-sectional Study

Introduction: Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common cancer globally and the seventh most common cause of cancer-related mortality. Tobacco use, alcohol consumption, and Human Papillomavirus (HPV) infection are prominent risk factors for HNSCC. HPVpositive Oral Squamous Cell Carcinoma (OSCC) differs from HPV-negative OSCC in terms of risk factors, preferential site of origin, age, histomorphological features, molecular genetic alterations, and prognosis. The prominent basaloid morphology and lobular growth of OSCCs are associated with p16 positivity and p53 negativity, respectively. Aim: To establish the immunohistochemical expression of p16 (p16INK4a) and p53 in OSCC and to assess their relationship with specific histomorphological features, in the form of solid growth of cells in a lobular configuration, small crowded cells with scant cytoplasm, dark hyperchromatic nuclei without nucleoli. Materials and Methods: The cross-sectional study involved fifty cases of OSCC over a two-year period from January 2017 to January 2019 at Army Hospital (R and R) Delhi Cantt. The intensity of p16 and p53 protein expression was graded as follows: no staining (0), weak staining (1), moderate staining (2), and strong staining (3). The proportion/percentage of staining for p16 and p53 protein expression was calculated as follows: 1-4% (1), 5-19% (2), 20-39% (3), 40-59% (4), 60-79% (5), and 80-100% (6) cells stained. A quick score of 0-1 (negative), 2-3 (weak positive), 4-5 (moderate positive), and &gt;6 (strong positive) was assessed. Cross tables were generated and the Chi-square test was used for testing associations. The Statistical Software for Data Science (STATA)-14 was used for statistical analysis. Results: A total of 50 cases of OSCC were analysed for histomorphological features and immunohistochemical patterns of p16 and p53. The age distribution showed that 8 (16%), 9 (18%), 18 (36%), 13 (26%), and 2 (4%) of the patients were in the age groups of 31-40 years, 41-50 years, 51-60 years, 61-70 years, and above 70 years, respectively. The gender distribution noted 42 (84%) males and 8 (16%) females. Genital and nongenital mucosa are usually involved by HPV subtypes 6, 11, 16, 18, and 16, 18, 11, 13, 2, respectively. HPV-16 has been demonstrated in 90-95% of all HPV-positive HNSCC cases, followed by HPV-18, HPV-31, and HPV-33. p53 is considered the guardian of the genome and controls the expression and activity of proteins involved in cell cycle regulation, DNA repair, cellular senescence, and apoptosis. More than 50% of all primary HNSCC exhibit p53 mutation. Conclusion: A significant correlation was observed between age, dysplasia, keratinisation, basaloid morphology versus p16 expression, and lobular growth, histological grade versus p53. An inverse relationship between p16 and p53 expressions was observed. The immunohistochemical expression of p16 as an immunohistochemical marker of HPV, along with p53, is recommended. Due to the constraint of the study period, the survival of the patients could not be assessed in correlation with p16 and p53 expression.

Immunohistochemical Characterization of Gingival Fibromas.

Gingival fibromas (GFs) are fibrous lesions of the gingiva that are not well defined in the literature. They are histologically similar to peripheral ossifying fibromas (POFs), both being characterized as cellular proliferations of dense fibrous tissue, with POFs differing in that they demonstrate foci of calcification. This study aims to expand upon the immunohistochemical characterization of GFs, and to confirm their osteoblastic phenotype. Formalin fixed, paraffin embedded GFs, POFs and fibroepithelial polyps (FEPs) of the gingiva were examined. Immunohistochemical staining was performed for special AT-rich sequence binding protein 2 (SATB2), runt-related transcription factor 2 (RUNX2), osteocalcin and alpha-smooth muscle actin (αSMA). Sections were evaluated by light microscopy and the immunohistochemical staining patterns were assigned immunoreactive scores (IRS) based on percentage of stained cells and intensity of staining. GFs, POFs, and FEPs of the gingiva expressed osteoblastic markers SATB2, RUNX2 and osteocalcin. GFs and POFs expressed αSMA while FEPs of the gingiva did not. GFs and POFs had similar staining patterns of SATB2, RUNX2 and αSMA. These findings demonstrate that GFs and POFs exhibit a similar immunohistochemical profile, and supports a theory that GFs are osteoblastic lesions possibly related to POFs.

Further prognostic stratification of intestinal type of gastric adenocarcinoma by CDX2 expression pattern

Gastric cancer is one of the most deadly malignancies worldwide. It is routinely divided into 2 common histologic subtypes by the Lauren classification, intestinal type and diffuse type. In recent years, the intestinal type of gastric cancer has been found to represent a heterogeneous disease with divergent prognosis. Our objective was to investigate the CDX2/CK7 immunohistochemical pattern and its role in further stratifying this type of gastric cancer. Gastrectomy cases with a diagnosis of the intestinal type of gastric adenocarcinoma from a single large institution between 2008 and 2022 were collected. Forty-four cases with available blocks and enough tumor tissue were included in this study. Four different immunohistochemical patterns were identified: CDX2+/CK7+ (40.9%), CDX2-/CK7+ (34.1%), CDX2+/CK7- (18.2%), and CDX2-/CK7- (6.8%). Compared to CDX2-negative cases, CDX2-positive ones are more likely to present better prognostic histopathological features including early stage, less perineural and lymphovascular invasion, and lower nodal metastasis. In addition, CDX2 expression was associated with specific molecular features like HER2 overexpression and genetic alterations of receptor tyrosine kinase (TRK) genes including EGFR, ERBB2, ERBB3, DDR2, and MET. In conclusion, according to the CDX2 expression pattern, the intestinal type of gastric cancer could be further divided into 2 subgroups, which have different histopathological and molecular features and different prognosis.

Evaluation of Morphological and Immunohistochemical Patterns Associated with MELF Type of Myoinvasion in Type I Endometrial Carcinomas

Evaluation of Morphological and Immunohistochemical Patterns Associated with MELF Type of Myoinvasion in Type I Endometrial Carcinomas

Correlative Assessment of p53 Immunostaining Patterns and TP53 Mutation Status by Next-Generation Sequencing in High-Grade Endometrial Carcinomas.

TP53 mutations are frequently identified in the copy number-high molecular subgroup of endometrial carcinomas (ECs). P53 immunohistochemistry (IHC) is a widely used surrogate marker reflecting the mutational status of TP53 , and recent reports have shown ~95% concordance between the two methods in ECs. While these results are promising, studies evaluating the correlation between different p53 IHC staining patterns and comprehensive next-generation sequencing results are still limited. We compared the p53 IHC staining patterns, scored as wild-type, diffuse nuclear overexpression, null/complete absence, and cytoplasmic, to next-generation sequencing results reported by FoundationOneCDx in 43 high-grade ECs: 20 serous ECs, 9 mixed ECs with a serous component, 4 carcinosarcomas with a serous component, and 10 grade 3 endometrioid ECs. The concordance of p53 IHC and TP53 mutation status was 100% (43/43) overall, including 100% (33/33) concordance in tumors with a serous component and 100% (10/10) in endometrioid ECs. Among the 35 tumors with aberrant p53 expression the most commonly observed pattern was diffuse nuclear overexpression seen in 69% (24/35), followed by cytoplasmic staining in 17% (6/35), and complete absence of staining (null) in 14% (5/35) of tumors. Of the 6 tumors with cytoplasmic staining, 4 corresponded to missense mutations within the DNA binding domain (V157F in 2 tumors, and S127P and R280S, in 2 tumor each), while 2 corresponded to nonsense mutations in the tetramerization domain (p.E339*). Our results further support that p53 IHC can serve as an accurate predictor of TP53 alterations in ECs to aid the molecular-based tumor classification and the distinction between tumor histotypes, both of which play an important role in the assessment of clinical prognosis and therapeutic decision making. In addition, our data suggest, that the type and position of TP53 mutation may not directly correlate with the observed p53 IHC pattern in all tumors, and that there may be alternative mechanisms for cytoplasmic localization (other than mutations involving the nuclear localization domain), possibly due to conformational changes or posttranslational modifications of the aberrant p53 protein.

C-cell differentiation in the wall of an aberrant ultimobranchial sinus in the thyroid gland of an old rat.

In mammals, the thyroid gland possesses two types of endocrine cells, follicular cells and C cells, which have different functions but share a similar endodermal origin (although from different regions of the primitive pharynx). Specifically, follicular cells derive from the ventral pharyngeal floor, while C cells derive from the fourth pair of pharyngeal pouches through the ultimobranchial bodies (UBBs). Disruptions to human midline thyroid morphogenesis are relatively frequent and known as thyroid dysgenesis, which is the leading cause of congenital hypothyroidism. In contrast, fourth branchial apparatus anomalies are very rare clinical entities. The aim of this study was to analyze the morphological features and the immunohistochemical pattern of an aberrant ultimobranchial remnant, align with its persistent contribution to the formation of new C cells. The thyroid gland of an old rat was serially sectioned and immunostained for the following markers: calcitonin, thyroglobulin, cytokeratins, PCNA, P63, E-cadherin, beta-tubulin and CD3. We detected a spontaneous congenital defect in the organogenesis of the UBB in an old rat, giving rise to an 'ultimobranchial sinus', which was accompanied by thymic tissue and an abscess. The epithelium contained basal/stem cells and contributed to the formation of abundant C cells and scarce follicular cells. The ultimobranchial sinus is an exceptional finding for representing the first spontaneous abnormality in the development of UBB reported in rats, and the opportunity to observe sustained C-cell differentiation from stem cells in an old rat. These findings are consistent with a common origin of both C cells and follicular cells from UBB.