Probes for P16

Detection of human papilloma virus (HPV)-related head and neck squamous cell carcinoma (HNSCC) is important, as HPV-associated HNSCCs respond better to therapy. The RNAscope HPV-test is a novel RNA in situ hybridization (ISH) technique which strongly stains transcripts of E6 and E7 mRNA in formalin-fixed, paraffin-embedded tissue, with the potential to replace the indirect immunohistochemical (IHC) marker for p16 protein. A direct clinical comparison between p16 IHC and an automated RNA ISH using 18 probes has not been established. Samples from 27 formalin-fixed, paraffin-embedded HNSCC cases from the Emory University Hospital archives were stained using 18 individual RNA ISH probes for high-risk HPV (RNAscope 2.5 LS Probe ) on a Leica autostainer (Buffalo Grove, IL) and were compared with p16 IHC. Two pathologists reviewed and reached a consensus on all interpretations. The RNAscope technique was positive in 89% (24/27) and the p16 IHC was positive in 78% (21/27). The RNAscope was negative in 11.1% of samples (3/27) and the p16 IHC-negative in 22.2% (6/27). The RNA ISH detected 100% of the p16-positive IHC-stained slides and had a concordance of 88.9% (24/27). This easy to interpret automated staining method for 18 high-risk HPV genotypes is a feasible replacement for the indirect p16 IHC method.

HPV-related multiphenotypic sinonasal carcinoma (HMSC) is associated with high-risk human papillomavirus (HR-HPV) infection. Using HR-HPV mRNA in situ hybridization (ISH), we reported six new HMSC cases and compared their histopathology with that of sinonasal adenoid cystic carcinoma (ACC). Using p16 immunohistochemistry (IHC) and HR-HPV ISH, we retrospectively identified six HMSC cases. All HMSC cases were positive for HR-HPV mRNA ISH and p16 IHC. Two HMSC cases had overlying atypical squamous epithelium and one also had invasive squamous cell carcinoma (SCC). All HMSC were SOX10-positive whereas the overlying atypical squamous epithelium and the SCC were SOX10-negative. One atypical HMSC-like case was also identified which was positive for HR-HPV mRNA ISH, HR-HPV DNA ISH, SOX10 IHC, but negative for p16 IHC. This study showed that HR-HPV mRNA ISH was a useful tool to diagnose HMSC and had stronger signals than HR-HPV DNA ISH. HR-HPV E6/E7 mRNA could be identified in the overlying atypical squamous epithelium as well as the invasive SCC. A combination of p16 and SOX10 IHC will be a useful screening panel for HMSC followed by confirmatory HR-HPV mRNA ISH test.

Our understanding of adenoid basal tumors of the cervix has evolved over time. Most of the proliferations referred to as adenoid basal carcinoma have a clinically benign course-leading some to suggest the term "adenoid basal epithelioma." However, rarely, these may be associated with invasive carcinomas. These tumors have been etiologically linked with high-risk human papillomavirus (HR-HPV) infection. Here, we investigate the use of p16 immunohistochemistry and HR-HPV RNA in situ hybridization (ISH) in the classification of adenoid basal tumors of the cervix. Seventeen cases of adenoid basal tumors of the cervix were included. The patients' age ranged from 19 to 79 yr (average, 59 yr). p16 immunostain was performed on all cases and RNA ISH was performed in 4 cases with available formalin-fixed paraffin-embedded tissue. There were 11 low-grade tumors, 5 frankly invasive carcinomas, and 1 with histologic features that were intermediate between the former 2 categories. p16 immunostain was negative or showed patchy cytoplasmic staining in the low-grade tumors and was strongly and diffusely positive in the invasive carcinomas. HR-HPV RNA ISH was negative in the 3 low-grade tumors and was positive in 1 case of invasive carcinoma including the adenoid basal component. Distinct p16 immunostaining and HR-HPV RNA ISH patterns exist between low-grade adenoid basal tumors and invasive adenoid basal carcinomas. Our study indicates that p16 immunostaining and HR-HPV RNA ISH can be employed as useful ancillary tools in differentiating between noninvasive and invasive adenoid basal tumors along with careful histopathologic evaluation.

We sought to classify endocervical adenocarcinomas (ECAs) based on morphologic features linked to etiology (ie, human papillomavirus [HPV] infection), unlike the World Health Organization 2014 classification. The International Endocervical Adenocarcinoma Criteria and Classification (IECC criteria), described herein, distinguishes between human papillomavirus-associated adenocarcinoma (HPVA), recognized by the presence of luminal mitoses and apoptosis seen at scanning magnification, and no or limited HPVA features (nonhuman papillomavirus-associated adenocarcinoma [NHPVA]). HPVAs were then subcategorized based on cytoplasmic features (mostly to provide continuity with preexisting classification schemes), whereas NHPVAs were subclassified based on established criteria (ie, gastric-type, clear cell, etc.). Complete slide sets from 409 cases were collected from 7 institutions worldwide. Tissue microarrays representing 297 cases were constructed; immunohistochemistry (p16, p53, vimentin, progesterone receptor) and chromogenic in situ hybridization using an RNA-based probe set that recognizes 18 varieties of high-risk HPV were performed to validate IECC diagnoses. The 5 most common IECC diagnoses were usual-type (HPVA) (73% of cohort), gastric-type (NHPVA) (10%), mucinous adenocarcinoma of HPVA type, including intestinal, mucinous not otherwise specified, signet-ring, and invasive stratified mucin-producing carcinoma categories (9%), clear cell carcinoma (NHPVA) (3%) and adenocarcinoma, not otherwise specified (2%). Only 3 endometrioid carcinomas were recognized and all were NHPVA. When excluding cases thought to have suboptimal tissue processing, 90% and 95% of usual-type IECC cases overexpressed p16 and were HPV, whereas 37% and 3% of NHPVAs were p16 and HPV, respectively. The 1 HPV gastric-type carcinoma was found to have hybrid HPVA/NHPVA features on secondary review. NHPVA tumors were larger and occurred in significantly older patients, compared with HPVA tumors (P<0.001). The high-risk HPV chromogenic in situ hybridization probe set had superior sensitivity, specificity, and positive and negative predictive values (0.955, 0.968, 0.992, 0.833, respectively) compared with p16 immunohistochemistry (0.872, 0.632, 0.907, 0.545, respectively) to identify HPV-related usual carcinoma and mucinous carcinoma. IECC reliably segregates ECAs into HPVA and NHPVA types using morphology alone. This study confirms that usual-type ECAs are the most common type worldwide and that mucinous carcinomas comprise a mixture of HPVA and NHPVA, with gastric-type carcinoma being the major NHPVA type. Endometrioid and serous carcinomas of the endocervix are extraordinarily rare. Should clinical outcomes and genomic studies continue to support these findings, we recommend replacement of the World Health Organization 2014 criteria with the IECC 2017.

The oral cavity and oropharynx have historically been viewed as a single anatomic compartment of the head and neck. The practice of combining the oral cavity and oropharynx has recently been revised, largely owing to the observation that human papillomavirus (HPV)-related carcinogenesis has a strong predilection for the oropharynx but not the oral cavity. The purpose of this study was to determine whether HPV is evenly distributed across squamous cell carcinomas of the oropharynx including those sites that do not harbor tonsillar tissues such as the soft palate. A search of the medical records of the Johns Hopkins Hospital identified 32 primary squamous cell carcinomas of the soft palate (n=31) and posterior pharyngeal wall (n=1). All were evaluated with p16 immunohistochemistry and high-risk HPV in situ hybridization (ISH) (29 by RNA ISH and 3 by DNA ISH). For comparison, we also reviewed the medical records to obtain the HPV status of patients who had undergone HPV testing of primary tonsillar carcinomas over the same time interval as part of their clinical care. High-risk HPV as detected by ISH was present in just 1 (3.1%) of the 32 oropharyngeal squamous cell carcinomas, including 1 of 2 p16-positive carcinomas. The difference in HPV detection rates between tonsillar and nontonsillar sites was significant (1/32, 3.1% vs. 917/997, 92%; P<0.0001). HPV is not frequently detected in squamous cell carcinomas arising from nontonsillar regions of the oropharynx. Indeed, squamous cell carcinomas of the soft palate more closely resemble those arising in the oral cavity than those arising in areas of the oropharynx harboring tonsillar tissue. This finding not only further sharpens our understanding of site-specific targeting by HPV, but may have practical implications regarding HPV testing and even the way the oral vault is oncologically compartmentalized to partition HPV-positive from HPV-negative cancers.

Small cell neuroendocrine carcinoma (SCNEC) of the uterine cervix is a rare but extremely aggressive tumor. While high-risk human papillomavirus (HPV) is involved at an early stage of oncogenesis in many tumors, additional driving events have been postulated to facilitate the progression of SCNECs. Identification of oncogenic drivers could guide targeted therapy of this neoplasm. Clinicopathologic features of 10 cervical SCNECs are reported. Analyses included immunohistochemical evaluation of p16, p53, synaptophysin, and chromogranin expression; in situ hybridizations and polymerase chain reaction for high-risk HPV and/or HPV 18; and next-generation sequencing based on a 637-gene panel. The patients ranged in age from 28 to 68 years (mean, 45.6 y; median, 40.5 y). All tumors had diffuse p16 and synaptophysin expression. All but 1 tumor was positive for chromogranin (extent of staining ranged from focal to diffuse). HPV 18 was detected in 6 tumors and HPV 35 in 1 tumor. At least 1 driver mutation was detected in 8 tumors. Four cases harbored TP53 somatic mutations, 3 of which correlated with an aberrant p53 staining pattern. Four PIK3CA mutations (p.G106A, p.N345T, p.E545K, and p.E545D) were detected in 3 tumors, 2 of which also harbored TP53 mutations. Oncogenic driver mutations involving KRAS, Erbb2, c-Myc, NOTCH1, BCL6, or NCOA3 were detected in 4 tumors. Mutations in caretaker tumor suppressors PTEN, RB1, BRCA1, BRCA2, and ARID1B were also identified in 4 tumors that commonly coharbored activating oncogenic mutations. Targeted next-generation gene sequencing identified genetic alterations involving the MAPK, PI3K/AKT/mTOR, and TP53/BRCA pathways in SCNECs. The presence of genetic alterations that are amenable to targeted therapy in SCNECs offers the potential for individualized management strategies for treatment of this aggressive tumor.