Predictive value of immunohistochemistry in pre-malignant lesions of the gastrointestinal tract

Combined detection of P53, Ki67, P504S, and IMP3: Diagnostic implications for gastric cancer and precursor lesions

BACKGROUND

Differential diagnosis among atypical hyperplasia (AH) (including reparative hyperplasia and intestinal metaplasia), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and adenocarcinoma (AC) in gastric mucosal biopsies is challenging due to histomorphological overlaps, variability in pathological diagnosis consistency, and limited reproducibility.

AIM

To evaluate the diagnostic utility of P53, Ki67, P504S, and IMP3 in gastric cancer and its precancerous lesions, focusing on their effectiveness in distinguishing AH, LGD, HGD, and AC.

METHODS

From January 2018 to September 2020, a total of 185 gastric mucosal biopsy specimens were analyzed according to the pathological diagnostic criteria outlined in the World Health Organization Classification of Digestive System Tumors (2019). The specimens were categorized into four groups: AH, LGD, HGD, and AC. Immunohistochemistry was employed to assess the expression status of P53, Ki67, P504S, and IMP3. Intergroup comparisons were performed using the χ² test or Fisher's exact probability test to compare the differences in immunohistochemical markers across the distinct lesion groups.

RESULTS

The expression rate of P504S was highest in the LGD group (53.3%, 16/30), while IMP3 expression was highest in the AC group (41.9%, 26/62), followed by the HGD group (33.3%). Significant differences in P504S and IMP3 expression levels were observed among the four lesion groups (P < 0.001). Pairwise comparisons revealed statistically significant differences in P504S expression between the AH group and the LGD, HGD, and AC groups (P < 0.001), as well as significant variations in IMP3 expression between the AH group and the HGD and AC groups, and between the LGD group and the HGD and AC groups (P < 0.001). Additionally, significant correlations were found between P504S and the polarity expression pattern of Ki67, and between IMP3 and the mutation expression pattern of P53 (P < 0.001). The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC, respectively.

CONCLUSION

P504S is highly expressed in LGD and is associated with the Ki67 “polarity” expression pattern. IMP3 is highly expressed in HGD/AC and is correlated with the P53 mutation expression pattern. The combined detection of P504S with Ki67 and IMP3 with P53 increased the diagnostic sensitivity for LGD and HGD/AC, respectively. The rational use of P504S, Ki67, IMP3, and p53 can help distinguish gastric cancer and precancerous lesions, improving the early cancer diagnosis rate.

MYC overexpression in inflammatory bowel disease-associated conventional dysplasia and association of subsequent low-grade dysplasia in follow-up biopsies

OBJECTIVE

Diagnosis of inflammatory bowel disease (IBD)-associated dysplastic lesions can be challenging. This study aims to evaluate MYC immunohistochemistry (IHC) as a potential biomarker for IBD-associated dysplasia and compare its effectiveness with p53 IHC.

METHODS

The study cohort included resections from 12 IBD patients with carcinoma and concurrent conventional low-grade dysplasia (LGD), as well as biopsies from 21 patients with visible conventional LGD, which were followed up for 2 years with subsequent endoscopic examination. MYC and p53 IHC and MYC-FISH analysis were performed.

RESULTS

Sensitivity for LGD detection was 67% (8/12) and 50% (6/12) for MYC and p53, respectively, but the difference was not statistically significant (p = 0.2207). MYC and p53 overexpression were not always mutually exclusive, nor were they always present simultaneously. Patients who presented dysplasia in subsequent biopsies (7/21) were found to be more likely present with multiple LGD polyps and MYC-overexpressed LGD in the initial biopsies, compared to those without subsequent dysplasia (p < 0.05). These dysplastic lesions were commonly associated with chronic colitis (p = 0.0614). The distribution of LGD sites did not show a significant difference between patients with and without subsequent LGD. In MYC overexpressed cases, homogeneously strong nuclear expression was not identified in all dysplastic epithelial cells, and no MYC amplification was found in these cases by FISH.

CONCLUSION

MYC IHC can complement p53 IHC as an adjunct biomarker for diagnosing IBD-associated conventional LGD and can be used for the prediction of subsequent LGD in the follow-up biopsies combined with endoscopic features.

Reducing Racial Disparities in Surviving Gastrointestinal Cancer Will Require Looking Beyond the Fact That African-Americans Have Low Rates of Surgery

This article by Bliton and colleagues in this issue of the journal concludes that disproportionately low surgery rates among Black patients contribute to the known survival disparity between Blacks and Whites. Using data from the National Cancer Database (NCDB), they were able to address the implicit hypothesis that the measured outcome disparities are partly attributable to failure to deliver surgical care equitably. As with most good research on difficult and complex topics, it also raises interesting and provocative questions about the role of race in poor survival among African-American patients with gastrointestinal cancer. The main limitation of the NCDB is its inability to account for individual-level factors. Those things related to health behaviors, such as diet, physical activity, and tobacco use, but that also include characteristics of the built environment, comprehensive access to care measures, clinical decision-making, racial discrimination and other forms of psychosocial stress, and environmental contamination, would influence both the likelihood of getting cancer and the probability of having aggressive disease with poor prognosis. These factors also may be related to clinical decision-making. Suggestions are made to design studies and collect data that would help to inform future investigations to deepen our understanding of racial disparities in cancer survival.See related article by Bliton et al., p. 529.

p16 immunostaining in histological grading of anal squamous intraepithelial lesions: a systematic review and meta-analysis

p16 is the most widely studied biomarker in lower anogenital tract squamous intraepithelial lesions and, currently the only recommended biomarker for histological grade assessment. The aim of this systematic review and meta-analysis was to evaluate p16-positive rates according to anal squamous intraepithelial lesions/anal intraepithelial neoplasia (AIN) grade. Two investigators independently searched four electronic databases: PubMed, Web of Sciences, Scopus, and Embase from inception until August 2017. Studies that evaluated p16 immunostaining in histological samples of anal and/or perianal squamous intraepithelial lesions and defined a p16-positive result as diffuse block staining with nuclear or nuclear plus cytoplasmic staining were included. A meta-analysis was performed using a random effects model. Fifteen studies consisting of 790 samples were included. The proportion of p16 expression increased with the severity of histological grade. p16 positivity was 2% (95% CI: 0.2-5%) in normal histology, 12% (95% CI: 2-27%) in low-grade squamous intraepithelial lesions (LSILs)/AIN1 (excluding condylomas), 7% (95% CI: 2-13%) in all LSIL (AIN1/LSIL/condyloma), 76% (95% CI: 61-88%) in AIN2, and 90% (95% CI: 82-95%) in AIN3. For anal high-grade squamous intraepithelial lesions (HSILs), in studies using a two-tiered nomenclature, p16 positivity was 84% (95% CI: 66-96%) and for all HSIL (AIN2, AIN3, HSIL combined) it was 82% (95% CI: 72-91%). In summary, p16 positivity in anal squamous intraepithelial lesions appears to be in a similar range to the commonly described cervical squamous intraepithelial lesions, however, for anal low-grade lesions positivity seems to be lower.