Diagnostic Accuracy of Conventional Cell Blocks Along with p16INK4 and Ki67 Biomarkers as Triage Tests in Resource-poor Organized Cervical Cancer Screening Programs

Comparison of liquid-based cytology and cell blocks prepared from cell remnants for diagnosis of cervical pathology

BACKGROUND

Cervical cancer is a global public health problem with high mortality. Advances in screening programs for cervical cancer are considered key to eliminate cervical cancer. We aimed to examine the contribution of cell block analysis to the detection of epithelial cell abnormalities in cervical smear samples.

METHODS

A total of 559 patients with suspected cervical pathology were examined, and their samples were analyzed by both liquid-based cytology (LBC) and cell blocks. The biopsy results of 149 out of the 559 patients were obtained.

RESULTS

Of the 50 patients who were identified as HSIL by biopsy, only 12 were diagnosed as HSIL by the LBC method, 22 as LSIL, 12 as ASCUS, and 4 as ASC-H (p < 0.001). With the cell block analysis, results for these patients were: 20 HSIL, 17 LSIL, 7 NILM, 4 'unsatisfactory', and 2 ASC cases (p < 0.001). LBC detected only 1 of the 10 patients with biopsy-diagnosed tumors, while 7 of these were defined as HSIL, 1 as ASCUS and 1 as AGC. The results of cell block analysis in patients with biopsy-diagnosed tumors were as follows: 7 HSIL, 1 tumor, 1 ASC and 1 LSIL.

CONCLUSIONS

Cell block analysis might be superior to LBC in terms of diagnostic accuracy in cervical pathologies, particularly in the detection of HSIL. However, both methods were similarly poor in diagnosing tumors. Cell blocks may improve diagnostic accuracy and can be a complementary method to LBC, while having the advantage of revealing histological architecture.

Preliminary Study on the Expression of Testin, p16 and Ki-67 in the Cervical Intraepithelial Neoplasia

Cervical cancer is one of the most common malignant cancers in women worldwide. The 5-year survival rate is 65%; nevertheless, it depends on race, age, and clinical stage. In the oncogenesis of cervical cancer, persistent HPV infection plays a pivotal role. It disrupts the expression of key proteins as Ki-67, p16, involved in regulating the cell cycle. This study aimed to identify the potential role of testin in the diagnosis of cervical precancerous lesions (CIN). The study was performed on selected archival paraffin-embedded specimens of CIN1 (31), CIN2 (75), and CIN3 (123). Moderate positive correlation was observed between testin and Ki-67 as well as testin and p16 expression in all dysplastic lesions (r = 0.4209, r = 0.5681; p < 0.0001 for both). Statistical analysis showed stronger expression of the testin in dysplastic lesions vs. control group (p < 0.0001); moreover, expression was significantly higher in HSIL than LSIL group (p < 0.0024). In addition, a significantly stronger expression of testin was observed in CIN3 vs. CIN1 and CIN3 vs. CIN2. In our study, expression of Ki-67, p16, and testin increased gradually as the lesion progressed from LSIL to HSIL. The three markers complemented each other effectively, which may improve test sensitivity and specificity when used jointly.

Architectural aspects of cell-blocks as small biopsies

Cell-block preparations have become an essential part of integrated cytology diagnosis. They are essentially microbiopsies that are formalin fixed and embedded in paraffin. This has become more prevalent with greater sample procurement due to the advent of newer biopsy techniques and needles. Cell-blocks allow retrieval of small tissue fragments from cytology specimens that sometimes cannot be processed by alternate cytologic techniques. They represent concentrated, cell-enriched preparations that provide cytologists with the opportunity to evaluate cellular architecture, as well as to perform ancillary testing. A cell-block compatible sample may thus obviate the need for a more invasive procedure such as a tissue biopsy. Microscopic examination of cell-blocks is quick, avoids obscuring material, permits cells to be evaluated in one focal plane, and allows the histologic architecture such as glandular differentiation, papillary formations, and sometimes invasion to be easily identified. This new era of “cytohistology” accordingly requires practicing cytologists to become more familiar with histopathology. This review article discusses the benefit of various architectural patterns identifiable in cell-blocks employed as an adjunct to Pap tests, exfoliative fluid specimens, and fine-needle aspirations.