Objective: To evaluate the diagnostic utility and limitations of routine p16 and Ki-67 immunohistochemistry (IHC) in detecting high-grade squamous intraepithelial lesions (HSILs) in the uterine cervix. Methods: We reviewed 2,061 cervical biopsy records, including 271 morphologically indeterminate squamous lesions, evaluated using p16/Ki-67 IHC for HSIL detection or exclusion. HSIL was diagnosed based on p16 positivity and a high Ki-67 labeling index (Ki-LI). In cases that remained inconclusive after IHC, follow-up histological and/or cytological outcomes were assessed. Results: p16/Ki-67 IHC established a definitive diagnosis of either HSIL or non-HSIL in 74.2% (201/271) of morphologically indeterminate cases, whereas 25.8% (70/271) remained inconclusive. p16/Ki-67 IHC contributed to diagnosing 120 HSIL cases, representing 11.9% (120/1,011) of all HSILs cases and 44.3% (120/271) of morphologically indeterminate cases. Among the 70 inconclusive cases, 58 had available follow-up data, of which 22 were subsequently diagnosed with HSIL, including 12 within 1 month of the initial biopsy. HSIL outcomes were more frequent in cases with suspicious HSIL on the initial biopsy (66.7% [12/18]). Based on the p16/Ki-LI status observed in the initial biopsy, patients with HSIL outcomes were categorized into three groups: p16-positive/low Ki-LI (54.2% [13/24]), p16-negative/high Ki-LI (50.0% [5/10]), and p16-negative/low Ki-LI (16.7% [4/24]). Multiple comparisons revealed a significant difference between the p16-positive/low Ki-LI and p16-negative/low Ki-LI groups (Benjamini-Yekutieli adjusted P=0.0435), while other comparisons were not significant. Conclusion p16/Ki-67 IHC significantly improved the diagnostic performance for HSIL. In cases that remain inconclusive after IHC, IHC-based risk stratification offers a valuable approach for surveillance, thus mitigating delays in HSIL diagnosis.

Objective: To evaluate the diagnostic utility and limitations of routine p16 and Ki-67 immunohistochemistry (IHC) in detecting high-grade squamous intraepithelial lesions (HSILs) in the uterine cervix. Methods: We reviewed 2,061 cervical biopsy records, including 271 morphologically indeterminate squamous lesions, evaluated using p16/Ki-67 IHC for HSIL detection or exclusion. HSIL was diagnosed based on p16 positivity and a high Ki-67 labeling index (Ki-LI). In cases that remained inconclusive after IHC, follow-up histological and/or cytological outcomes were assessed. Results: p16/Ki-67 IHC established a definitive diagnosis of either HSIL or non-HSIL in 74.2% (201/271) of morphologically indeterminate cases, whereas 25.8% (70/271) remained inconclusive. p16/Ki-67 IHC contributed to diagnosing 120 HSIL cases, representing 11.9% (120/1,011) of all HSILs cases and 44.3% (120/271) of morphologically indeterminate cases. Among the 70 inconclusive cases, 58 had available follow-up data, of which 22 were subsequently diagnosed with HSIL, including 12 within 1 month of the initial biopsy. HSIL outcomes were more frequent in cases with suspicious HSIL on the initial biopsy (66.7% [12/18]). Based on the p16/Ki-LI status observed in the initial biopsy, patients with HSIL outcomes were categorized into three groups: p16-positive/low Ki-LI (54.2% [13/24]), p16-negative/high Ki-LI (50.0% [5/10]), and p16-negative/low Ki-LI (16.7% [4/24]). Multiple comparisons revealed a significant difference between the p16-positive/low Ki-LI and p16-negative/low Ki-LI groups (Benjamini-Yekutieli adjusted P=0.0435), while other comparisons were not significant. Conclusion p16/Ki-67 IHC significantly improved the diagnostic performance for HSIL. In cases that remain inconclusive after IHC, IHC-based risk stratification offers a valuable approach for surveillance, thus mitigating delays in HSIL diagnosis.

Objective: To evaluate the diagnostic utility and limitations of routine p16 and Ki-67 immunohistochemistry (IHC) in detecting high-grade squamous intraepithelial lesions (HSILs) in the uterine cervix. Methods: We reviewed 2,061 cervical biopsy records, including 271 morphologically indeterminate squamous lesions, evaluated using p16/Ki-67 IHC for HSIL detection or exclusion. HSIL was diagnosed based on p16 positivity and a high Ki-67 labeling index (Ki-LI). In cases that remained inconclusive after IHC, follow-up histological and/or cytological outcomes were assessed. Results: p16/Ki-67 IHC established a definitive diagnosis of either HSIL or non-HSIL in 74.2% (201/271) of morphologically indeterminate cases, whereas 25.8% (70/271) remained inconclusive. p16/Ki-67 IHC contributed to diagnosing 120 HSIL cases, representing 11.9% (120/1,011) of all HSILs cases and 44.3% (120/271) of morphologically indeterminate cases. Among the 70 inconclusive cases, 58 had available follow-up data, of which 22 were subsequently diagnosed with HSIL, including 12 within 1 month of the initial biopsy. HSIL outcomes were more frequent in cases with suspicious HSIL on the initial biopsy (66.7% [12/18]). Based on the p16/Ki-LI status observed in the initial biopsy, patients with HSIL outcomes were categorized into three groups: p16-positive/low Ki-LI (54.2% [13/24]), p16-negative/high Ki-LI (50.0% [5/10]), and p16-negative/low Ki-LI (16.7% [4/24]). Multiple comparisons revealed a significant difference between the p16-positive/low Ki-LI and p16-negative/low Ki-LI groups (Benjamini-Yekutieli adjusted P=0.0435), while other comparisons were not significant. Conclusion p16/Ki-67 IHC significantly improved the diagnostic performance for HSIL. In cases that remain inconclusive after IHC, IHC-based risk stratification offers a valuable approach for surveillance, thus mitigating delays in HSIL diagnosis.

Objective: To evaluate the diagnostic utility and limitations of routine p16 and Ki-67 immunohistochemistry (IHC) in detecting high-grade squamous intraepithelial lesions (HSILs) in the uterine cervix. Methods: We reviewed 2,061 cervical biopsy records, including 271 morphologically indeterminate squamous lesions, evaluated using p16/Ki-67 IHC for HSIL detection or exclusion. HSIL was diagnosed based on p16 positivity and a high Ki-67 labeling index (Ki-LI). In cases that remained inconclusive after IHC, follow-up histological and/or cytological outcomes were assessed. Results: p16/Ki-67 IHC established a definitive diagnosis of either HSIL or non-HSIL in 74.2% (201/271) of morphologically indeterminate cases, whereas 25.8% (70/271) remained inconclusive. p16/Ki-67 IHC contributed to diagnosing 120 HSIL cases, representing 11.9% (120/1,011) of all HSILs cases and 44.3% (120/271) of morphologically indeterminate cases. Among the 70 inconclusive cases, 58 had available follow-up data, of which 22 were subsequently diagnosed with HSIL, including 12 within 1 month of the initial biopsy. HSIL outcomes were more frequent in cases with suspicious HSIL on the initial biopsy (66.7% [12/18]). Based on the p16/Ki-LI status observed in the initial biopsy, patients with HSIL outcomes were categorized into three groups: p16-positive/low Ki-LI (54.2% [13/24]), p16-negative/high Ki-LI (50.0% [5/10]), and p16-negative/low Ki-LI (16.7% [4/24]). Multiple comparisons revealed a significant difference between the p16-positive/low Ki-LI and p16-negative/low Ki-LI groups (Benjamini-Yekutieli adjusted P=0.0435), while other comparisons were not significant. Conclusion p16/Ki-67 IHC significantly improved the diagnostic performance for HSIL. In cases that remain inconclusive after IHC, IHC-based risk stratification offers a valuable approach for surveillance, thus mitigating delays in HSIL diagnosis.

Objective: To evaluate the diagnostic utility and limitations of routine p16 and Ki-67 immunohistochemistry (IHC) in detecting high-grade squamous intraepithelial lesions (HSILs) in the uterine cervix. Methods: We reviewed 2,061 cervical biopsy records, including 271 morphologically indeterminate squamous lesions, evaluated using p16/Ki-67 IHC for HSIL detection or exclusion. HSIL was diagnosed based on p16 positivity and a high Ki-67 labeling index (Ki-LI). In cases that remained inconclusive after IHC, follow-up histological and/or cytological outcomes were assessed. Results: p16/Ki-67 IHC established a definitive diagnosis of either HSIL or non-HSIL in 74.2% (201/271) of morphologically indeterminate cases, whereas 25.8% (70/271) remained inconclusive. p16/Ki-67 IHC contributed to diagnosing 120 HSIL cases, representing 11.9% (120/1,011) of all HSILs cases and 44.3% (120/271) of morphologically indeterminate cases. Among the 70 inconclusive cases, 58 had available follow-up data, of which 22 were subsequently diagnosed with HSIL, including 12 within 1 month of the initial biopsy. HSIL outcomes were more frequent in cases with suspicious HSIL on the initial biopsy (66.7% [12/18]). Based on the p16/Ki-LI status observed in the initial biopsy, patients with HSIL outcomes were categorized into three groups: p16-positive/low Ki-LI (54.2% [13/24]), p16-negative/high Ki-LI (50.0% [5/10]), and p16-negative/low Ki-LI (16.7% [4/24]). Multiple comparisons revealed a significant difference between the p16-positive/low Ki-LI and p16-negative/low Ki-LI groups (Benjamini-Yekutieli adjusted P=0.0435), while other comparisons were not significant. Conclusion p16/Ki-67 IHC significantly improved the diagnostic performance for HSIL. In cases that remain inconclusive after IHC, IHC-based risk stratification offers a valuable approach for surveillance, thus mitigating delays in HSIL diagnosis.

Objective: Previously, we reported that insulinoma-associated protein 1 (INSM1) immunohistochemistry (IHC) showed high sensitivity for neuroendocrine carcinoma of the uterine cervix and was an effective method for histopathological diagnosis, but that its specificity remained to be verified. Therefore, the aim was to verify the specificity of INSM1 IHC for a large number of non-neuroendocrine neoplasia (NEN) of the cervix. Methods: RNA sequences were performed for cell lines of small cell carcinoma (TCYIK), squamous cell carcinoma (SiHa), and adenocarcinoma (HeLa). A total of 104 cases of formalin-fixed and paraffin-embedded specimens, 16 cases of cervical NEN and 88 cases of cervical non-NEN, were evaluated immunohistochemically for conventional neuroendocrine markers and INSM1. All processes without antigen retrieval were performed by an automated IHC system. Results: The transcripts per million levels of INSM1 in RNA sequences were 1505 in TCYIK, 0 in SiHa, and HeLa. INSM1 immunoreactivity was shown only in the TCYIK. Immunohistochemical results showed that 15 cases of cervical NEN showed positive for INSM1; the positivity score of the tumor cell population and the stain strength for INSM1 were high. Two of the 88 cases of cervical non-NENs were positive for INSM1 in one case each of typical adenocarcinoma and squamous cell carcinoma. The sensitivity of INSM1 for cervical NEN was 94%; specificity, 98%; the positive predictive value, 88%; and the negative predictive value, 99%. Conclusion INSM1 is an adjunctive diagnostic method with excellent specificity and sensitivity for diagnosing cervical NEN. Higher specificity can be obtained if morphological evaluation is also performed.