Use of p53 immunohistochemistry in conjunction with routine histology improves risk stratification of patients with Barrett's oesophagus during routine clinical care

The future is now: advancing p53 immunohistochemistry in Barrett's oesophagus and its implication for the everyday pathologist

Barrett's oesophagus (BE) is a precancerous condition where the normal squamous epithelium of the distal oesophagus is replaced by specialised intestinal-type columnar epithelium. Patients with BE have an increased risk of developing oesophageal adenocarcinoma (EAC). p53 is a tumour suppressor protein frequently mutated in BE, and its overexpression is detectable by immunohistochemistry (IHC) and correlates with TP53 mutations. This review summarises recent literature on p53 IHC as a diagnostic aid for dysplasia and a predictive biomarker of neoplastic progression risk in BE. While there is a vast amount of literature on this topic, there are no established criteria for what constitutes an abnormal p53 immunohistochemical result in the setting of BE. Multiple studies show that p53 IHC improves interobserver agreement and diagnostic confidence for low-grade dysplasia, high-grade dysplasia and EAC compared to histology alone. Establishing easy-to-use, reproducible and practical diagnostic criteria that can be applied to routine daily practice is urgently needed. p53 IHC overexpression in non-dysplastic BE indicates an increased neoplastic progression risk. Emerging technologies such as next-generation sequencing may offer higher sensitivity for detecting neoplastic clones. While the haematoxylin and eosin stain remains the most powerful tool, p53 IHC is a valuable adjunct for determining and diagnosing dysplasia. Although p53 is helpful in predicting the risk of dysplasia in non-dysplastic Barrett's oesophagus, its sensitivity is low, limiting its routine use in this context.

TP53 Alterations Are an Independent Adverse Prognostic Indicator in Pseudomyxoma Peritonei of Appendiceal Origin Following Cytoreductive Surgery and Intraperitoneal Chemotherapy

Histologic grade is a key predictor for pseudomyxoma peritonei (PMP) of appendiceal origin that is used to guide clinical management. However, some tumors demonstrate disease behavior that deviates from their histologic grade. A recent study suggested that TP53, GNAS , and RAS mutation analysis could stratify tumors into distinct molecular groups with different prognosis. We investigated molecular alterations in 114 patients with PMP of appendiceal origin who were uniformly treated with cytoreductive surgery with intraperitoneal chemotherapy (CRS+IPCT). Tumors were separated into 4 groups based on their predominant genomic alteration: RAS -mut, GNAS -mut, TP53 -mut, and triple-negative ( RAS/GNAS/TP53 -wildtype). The results were correlated with World Health Organization (WHO) grade, peritoneal carcinomatosis index (PCI), completeness of cytoreduction (CC) score, and overall survival (OS) from the time of CRS+IPCT using multivariate Cox proportional hazard analysis. Fifty percent of TP53 -mut were WHO grade 3 compared with 38% triple-negative, 10% RAS -mut, and 7% GNAS -mut tumors ( P <0.001). The TP53 -mut group exhibited a significantly reduced OS compared with other groups ( P <0.001). No significant OS difference was identified between RAS -mut, GNAS -mut, and triple-negative groups ( P >0.05). In grade 3 PMP, TP53 -mut was significantly associated with reduced OS ( P =0.002). In the multivariate analysis for OS after CRS+IPCT, TP53 -mut [hazard ratio (HR) 3.23, P =0.004] and WHO grade (grade 2 HR 2.73, P =0.03 and grade 3 HR 5.67, P <0.001) were the only independent predictors of survival. Our results suggest that, in addition to tumor grade, TP53 status may help to provide a more patient-centered approach in guiding therapy in PMP.

Defining an abnormal p53 immunohistochemical stain in Barrett's oesophagus-related dysplasia: a single-positive crypt is a sensitive and specific marker of dysplasia

AIMS

p53 is an independent risk stratification marker in Barrett's oesophagus (BE), but no universally accepted definition exists for abnormal p53 staining. Herein, we assess p53 stains in two cohorts to: (1) define abnormal p53 staining in BE-related dysplasia (BERD) and (2) assess the specificity and sensitivity of this cut-point for the diagnosis of dysplasia.

METHODS

Cohort 1 (n = 313) included (1) dysplastic BE biopsies, (2) prior non-dysplastic BE (NDBE) biopsies from the same patients and (3) NDBE biopsies from patients who never progressed to dysplasia. Cohort 2 (n = 191) consisted of BE biopsies in which p53 staining aided in diagnosing dysplasia. Automated p53 staining quantification was performed on cohort 1. A semiquantitative p53 analysis, performed on both cohorts, included: (1) number of strongly positive glands, (2) strong glandular surface staining, (3) percentage of strongly positive glands and (4) null phenotype.

RESULTS

NDBE biopsies from cohort 1 patients who progressed to dysplasia were more likely to show p53 positivity than non-progressors (16.9 versus 0.6%) (P = 0.0001). The optimal quantitative cut-point for distinguishing dysplastic from never-dysplasia biopsies was 10 strongly positive cells. By semiquantitative analysis, a single strongly p53-positive gland distinguished dysplastic from never-dysplasia BE (sensitivity 98.6%, specificity 99.4%). The semiquantitative and quantitative analyses correlated (P = 0.0001). In cohort 2, the sensitivity and specificity for BERD of ≥ 1 strongly positive p53 gland were 86.0 and 88.6%.

CONCLUSIONS

A single strongly positive p53 gland is sensitive and specific for BERD. Automated p53 analysis may reduce subjectivity associated with the diagnosis of BERD.

The utility of P53 immunohistochemistry in the diagnosis of Barrett's esophagus with indefinite for dysplasia

BACKGROUND

Barrett's esophagus with indefinite for dysplasia (BE-IND) is a subjective diagnosis with a low interobserver agreement (IOA) among pathologists and uncertain clinical implications. This study aimed to assess the utility of p53 immunohistochemistry (p53-IHC) in assessing BE-IND specimens.

METHODS

Archive endoscopic biopsies with a BE-IND diagnosis from two academic centers were analyzed. Firstly, hematoxylin and eosin-stained slides (H&E) were reviewed by four expert GI pathologists allocated into two groups (A and B). After a wash-out period of at least eight weeks, H&E slides were re-assessed side-to-side with p53-IHC available. We compared the rate of changed diagnosis and the IOA for all BE grades before and after p53-IHC.

FINDINGS

We included 216 BE-IND specimens from 185 patients, of which 44.0% and 32.9% were confirmed after H&E slide revision by Groups A and B, respectively. Over half of the cases were reclassified to a non-dysplastic BE (NDBE), while 5.6% of cases in Group A and 7.4% in Group B were reclassified to definite dysplasia. The IOA for NDBE, BE-IND, low-grade dysplasia (LGD), and high-grade dysplasia (HGD)/intramucosal cancer (IMC) was 0.31, 0.21, -0.03, and -0.02, respectively. Use of p53-IHC led to a >40% reduction in BE-IND diagnoses (P<.001), and increased IOA for all BE grades (κ=0.46 [NDBE], 0.26 [BE-IND], 0.49 [LGD], 0.35 [HGD/IMC]). An aberrant p53-IHC pattern significantly increased the likelihood of reclassifying BE-IND to definite dysplasia (odds ratio 44.3, 95%CI:18.8-113.0).

INTERPRETATION

P53-IHC reduces the rate of BE-IND diagnoses and improves the IOA among pathologists when reporting BE with equivocal epithelial changes.

The risk of neoplasia in patients with Barrett's esophagus indefinite for dysplasia: a multicenter cohort study

BACKGROUND AND AIMS

Current understanding of the risk of neoplastic progression in patients with Barrett's esophagus with indefinite dysplasia (BE-IND) stems from small retrospective and pathology registry studies. In this multicenter cohort study, we aimed to determine the incidence and prevalence of neoplasia in BE-IND.

METHODS

Patients with confirmed BE-IND from 2 academic centers were included if they had no previous evidence of dysplasia and underwent endoscopic follow-up (FU) of ≥1 year. The rate of progression to neoplasia was calculated and categorized as prevalent (progression within 1 year of FU) and incident (progression after 1 year of FU). Multivariable regression adjusted for relevant clinical features was performed to identify risk factors for progression.

RESULTS

Four hundred sixty-five patients diagnosed with BE-IND were identified between 1997 and 2017, of which 223 (48.0%) were excluded. Of the remaining 242 patients, 184 (76.0%) had no evidence of dysplasia during FU. In 23 patients (9.5%), prevalent neoplasia occurred (20 low-grade dysplasia [LGD], 2 high-grade dysplasia [HGD], 1 intramucosal cancer [IMC]), whereas 35 patients (14.5%) developed incident neoplasia (27 LGD, 5 HGD, 3 IMC), after a median 1.5 years (interquartile range, 0.6-3.2 years). The incidence rates of any neoplasia and HGD/IMC were 3.2 and 0.6 cases/100 patient-years, respectively. BE length correlated with an increased risk of prevalent (odds ratio, 1.18 per 1 cm; 95% confidence interval, 1.02-1.38; P = .033) and incident neoplasia (odds ratio, 1.02; 95% confidence interval, 1.00-1.03; P = .016).

CONCLUSION

Patients with BE-IND should be closely monitored, because nearly a quarter harbor or will shortly develop dysplasia. BE length is a clinical predictor of neoplastic progression; however, more-accurate molecular biomarkers for risk stratification are warranted.

Combined histopathological risk score using TP53 protein expression, CD8+ T cell density and intratumoral budding is an independent predictor of neoadjuvant therapy response in rectal adenocarcinoma

AIMS

Neoadjuvant therapy is the recommended treatment for locally advanced rectal adenocarcinoma; however, there remains significant variability in response to therapy. Tumour protein 53 (TP53) has been associated with therapy response and prognosis with conflicting data. Recently, we demonstrated that immune cell density and intratumoral budding (ITB) are predictive factors in rectal cancer. We investigated the predictive value of TP53 immunohistochemistry with CD8⁺ T cell density and ITB on pretreatment biopsies of rectal adenocarcinoma for response to neoadjuvant therapy.

METHODS AND RESULTS

Pretreatment biopsies of rectal adenocarcinoma from 117 patients with neoadjuvant therapy were analysed for TP53 expression by immunohistochemistry, ITB, CD8⁺ T cell density and mismatch repair protein (MMR) status. Most rectal adenocarcinomas displayed aberrant TP53 expression (86 of 117, 74%). Compared to wild-type TP53, aberrant TP53 expression was associated with proficient MMR status (P = 0.003) and low CD8⁺ T cell density (P = 0.001). Aberrant TP53 was significantly associated with a partial to poor response to neoadjuvant therapy [odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.04-5.62, P = 0.04]. A combined histopathological risk score (HRS) was created using CD8⁺ T cell density, ITB and TP53 expression. Patients were separated into low (none to one factor) and high (two to three factors) HRS categories. In the multivariable model, patients with a high HRS were 3.25-fold more likely to have a partial or poor response to neoadjuvant therapy (95% CI = 1.48-7.11, P = 0.003).

CONCLUSIONS

Our study demonstrates that aberrant TP53 expression, high ITB and low CD8⁺ T cell density in pretreatment biopsies can help predict response to neoadjuvant therapy. These biomarkers may be helpful in identifying patients at risk for therapy resistance.

Is Malignant Potential of Barrett's Esophagus Predictable by Endoscopy Findings?

Given that endoscopic findings can be used to predict the potential of neoplastic progression in Barrett's esophagus (BE) cases, the detection rate of dysplastic Barrett's lesions may become higher even in laborious endoscopic surveillance because a special attention is consequently paid. However, endoscopic findings for effective detection of the risk of neoplastic progression to esophageal adenocarcinoma (EAC) have not been confirmed, though some typical appearances are suggestive. In the present review, endoscopic findings that can be used predict malignant potential to EAC in BE cases are discussed. Conventional results obtained with white light endoscopy, such as length of BE, presence of esophagitis, ulceration, hiatal hernia, and nodularity, are used as indicators of a higher risk of neoplastic progression. However, there are controversies in some of those findings. Absence of palisade vessels may be also a new candidate predictor, as that reveals degree of intense inflammation and of cyclooxygenase-2 protein expression with accelerated cellular proliferation. Furthermore, an open type of mucosal pattern and enriched stromal blood vessels, which can be observed by image-enhanced endoscopy, including narrow band imaging, have been confirmed as factors useful for prediction of neoplastic progression of BE because they indicate more frequent cyclooxygenase-2 protein expression along with accelerated cellular proliferation. Should the malignant potential of BE be shown predictable by these endoscopic findings, that would simplify methods used for an effective surveillance, because patients requiring careful monitoring would be more easily identified. Development in the near future of a comprehensive scoring system for BE based on clinical factors, biomarkers and endoscopic predictors is required.

Neoplastic and pre-neoplastic lesions of the oesophagus and gastro-oesophageal junction

Oesophageal and gastro-oesophageal junction (GOJ) neoplasms, and their predisposing conditions, may be encountered by the practicing pathologist both as biopsy samples and as surgical specimens in daily practice. Changes in incidence of oesophageal squamous cell carcinomas (such as a decrease in western countries) and in oesophageal and GOJ adenocarcinomas (such as a sharp increase in western countries) are being reported globally. New modes of treatment have changed our histologic reports as specific aspects must be detailed such as in post endoscopic resections or with regards to post neo-adjuvant therapy tumour regression grades. The main aim of this overview is therefore to provide an up-to-date, easily available and clear diagnostic approach to neoplastic and pre-neoplastic conditions of the oesophagus and GOJ, based on the most recent available guidelines and literature.