Identification of a Novel Long Non-coding RNA, lnc-ATMIN-4:2, and its Clinicopathological and Prognostic Significance in Advanced Gastric Cancer.

BACKGROUND/AIM: Long non-coding RNAs (lncRNAs) are emerging as significant regulators of gene expression and a novel promising biomarker for cancer diagnosis and prognosis. This study identified a novel, differentially expressed lncRNA in advanced gastric cancer (AGC), Inc-ATMIN-4:2, and evaluated its clinicopathological and prognostic significance. PATIENTS AND METHODS: Whole transcriptome sequencing was performed to identify differentially expressed lncRNAs in AGC tissue samples. We also analyzed lnc-ATMIN-4:2 expression in 317 patients with AGC using RNA in situ hybridization. RESULTS: High (>30 dots) lnc-ATMIN-4:2 expression significantly correlated with younger age, poorly differentiated histology, diffuse type, deeper invasion depth, perineural invasion, lymph node metastasis, and higher stage group. In addition, high lnc-ATMIN-4:2 expression was significantly associated with worse overall survival in patients with AGC. CONCLUSION: This study elucidated the significance of lncRNAs in AGC and indicated the value of lnc-ATMIN-4:2 expression as a predictive biomarker for the overall survival of patients with AGC.

Identification of novel DNA hypermethylation of the adenylate kinase 5 promoter in colorectal adenocarcinoma.

Adenylate kinase 5 (AK5) belongs to the adenylate kinase family that catalyses reversible phosphate transfer between adenine nucleotides, and it is related to various energetic signalling mechanisms. However, the role of AK5 in colorectal cancer (CRC) has not been reported. In this study, AK5 was significantly hypermethylated in CRC compared to adjacent normal tissues (P < 0.0001) and normal tissues (P = 0.0015). Although the difference in mRNA expression was not statistically significant in all of them, the selected 49 cases of CRC tissues with AK5 hypermethylation with the cut off value of 40% showed a significant inverse correlation with mRNA expression (P = 0.0003). DNA methylation of AK5 promoter significantly decreased and AK5 expression recovered by 5-aza-2'-deoxycytidine, DNA methyltransferase inhibitor in CRC cell lines. In addition, AK5 promoter activity significantly decreased due to DNA methyltransferase, and it increased due to 5-aza. Moreover, AK5 regulated the phosphorylated AMPK and mTOR phosphorylation and inhibited the cell migration and cell invasion in CRC cell lines. Furthermore, low AK5 expression is associated with poor differentiation (P = 0.014). These results demonstrate that the AK5 promoter is frequently hypermethylated and induced methylation-mediated gene down-regulation. AK5 expression regulates AMPK/mTOR signalling and may be closely related to metastasis in colorectal adenocarcinoma.

NPC2 expression in thyroid tumors and its possible diagnostic utility.

Histopathologic diagnosis of thyroid lesions is sometimes difficult and may require the assistance of immunohistochemistry. Currently-used immunohistochemical biomarkers share the weakness of staining both papillary thyroid carcinoma and other non-papillary thyroid lesions. We examined NPC2 as an immunohistochemical marker in various thyroid lesions to determine the subcellular localization of the immunohistochemistry signal and evaluated the value of NPC2 as a diagnostic marker of papillary thyroid carcinoma. NPC2 immunostaining was performed on various thyroid tumors and tumor-like lesions. The immunostaining revealed significantly different patterns for papillary carcinomas and the other lesions. Papillary carcinomas exhibited moderate to strong granular cytoplasmic staining, often with basal membranous accentuation. In contrast, the other lesions showed mostly weak cytoplasmic staining, often with apical membranous accentuation. The subcellular localization of NPC2 provided insight into contrasting histopathologic morphology and reversed cellular polarity between the papillary patterns of papillary carcinomas and the follicular patterns of non-papillary carcinoma lesions. The diagnostic characteristics of NPC2 immunohistochemistry for non-follicular papillary carcinomas versus non-papillary carcinoma lesions were a sensitivity of 97.3%, specificity of 96.9%, positive predictive value of 94.7%, and negative predictive value of 98.4%. Significant differences were present between the two staining patterns in papillary carcinoma relative to mean age, nodal metastasis, and follicular and non-follicular variants (P = 0.02, P = 0.03, and P = 0.000, respectively). In conclusion, our evaluation of the subcellular localization of NPC2 using immunohistochemistry demonstrated possible value of NPC2 as a biomarker and provided insight into the morphologic characteristics of papillary carcinoma.

Different Immunohistochemical Localization of Fatty Acid Binding Protein 5 in Actinic Keratosis Compared with That in Bowen's Disease: A Retrospective Study.

ABSTRACT: Actinic keratosis (AK) and Bowen's disease (BD) are common premalignant lesions of invasive squamous cell carcinoma that have different pathogenesis and clinical significance. Fatty acid-binding protein 5 (FABP5) is responsible for keratinocyte homeostasis and differentiation; however, no study has revealed its expression in AK and BD. Our study aimed to investigate the differential expression and significance of FABP5 in these lesions. Patients with pathologically confirmed cases of AK (n = 37) and BD (n = 12) were included in this study. FABP5 immunostaining pattern was assessed in the normal skin, AK and BD lesions, with a focus on the staining patterns of basal cells, atypical keratinocytes, and uninvolved epidermal keratinocytes. All patients with AK showed negative FABP5 expression in the atypical cells in the basal layer, whereas the uninvolved upper layers showed diffuse, strong FABP5 expression, regardless of the grade of AK. All patients with BD showed heterogeneous and diffuse FABP5 expression in atypical cells of all layers of the epidermis. This study is the first to investigate the role of FABP5 in premalignant skin lesions. The unique immunohistochemical localization of the FABP5 can be a helpful diagnostic marker, and altered fatty acid metabolism may be the key in understanding the different pathophysiology of AK and BD.

BRCA1-associated protein 1 expression and prognostic role in prostate adenocarcinoma.

Purpose: As prostate cancer (PCa) is the second most commonly diagnosed cancer worldwide, finding novel markers for prognosis is crucial. BRCA1-associated protein 1 (BAP-1), a nuclear-localized deubiquitinating enzyme, has been reported in several human cancers. However, its prognostic role in PCa remains unknown. Herein, we assessed the prognostic and clinicopathologic significance of BAP-1 in PCa. Materials and Methods: Seventy surgical specimens from radical prostatectomy cases were examined. Two cores per case were selected for construction of tissue microarrays (TMAs). After the exclusion of two cases because of tissue sparsity, BAP-1 immunohistochemical expression was evaluated in 68 cases of formalin-fixed, paraffin-embedded TMA tissue blocks. The immunohistochemical stain was scored according to proportion of nuclear staining: negative (<10% of tumor cells) or positive (≥10% of tumor cells). Results: BAP-1 expression was negative in 30 cases (44.1%) and positive in 38 cases (55.9%). Positive BAP-1 expression was more common in pT3b disease than in pT2 (p=0.038). A high preoperative prostate-specific antigen level was correlated with BAP-1 expression (p=0.014). Age, lymphovascular invasion, perineural invasion, and grade group were not significantly correlated with BAP-1 expression. Patients with positive BAP-1 expression showed significantly shorter disease-free survival (p=0.013). Additionally, BAP-1 was an independent prognostic factor of PCa (p=0.035; hazard ratio, 9.277; 95% confidence interval, 1.165-73.892). Conclusions: Our study findings showed an association of BAP-1 expression with poor PCa prognosis and suggest a potential role for BAP-1 as a prognostic biomarker for PCa.

Morule-like features in pulmonary adenocarcinoma associated with epidermal growth factor receptor mutations: two case reports with targeted next-generation sequencing analysis.

Morules, or morule-like features, can be identified in benign and malignant lesions in various organs. Morular features are unusual in pulmonary adenocarcinoma cases with only 26 cases reported to date. Here, we describe two cases of pulmonary adenocarcinoma with morule-like features in Korean women. One patient had a non-mucinous-type adenocarcinoma in situ and the other had an acinarpredominant adenocarcinoma with a micropapillary component. Both patients showed multiple intra-alveolar, nodular, whorled proliferative foci composed of atypical spindle cells with eosinophilic cytoplasm. Targeted next-generation sequencing was performed on DNA extracted from formalin-fixed paraffin-embedded samples of the tumors. Results showed unusual epidermal growth factor receptor (EGFR) mutations, which are associated with drug resistance to EGFR tyrosine kinase inhibitors, revealing the importance of identifying morule-like features in pulmonary adenocarcinoma and the need for additional study, since there are few reported cases.

Long noncoding RNA HOTTIP overexpression: A potential prognostic biomarker in prostate cancer.

HOXA transcript at the distal tip (HOTTIP) is a long noncoding RNA (lncRNA), which is >200 nucleotides in length. HOTTIP expression has been demonstrated to play a crucial oncogenic role in cancer pathogenesis, and is said to be associated with poor human cancer prognosis. In prostate cancer, HOTTIP has been identified as an oncogene, but its clinicopathologic significance remains unclear. Array-based qRT-PCR was used to investigate lncRNA levels in 10 pairs of prostate cancer tissues and non-neoplastic parenchyma. Tissue microarray (TMA) was constructed using a total of 70 surgically resected prostatic adenocarcinoma tissues obtained from the Korea University Anam Hospital from 2009 to 2013. HOTTIP expression was determined by RNA in situ hybridization(ISH) and was correlated with clinicopathologic features. Increased HOTTIP expression was observed in all available prostate cancer tissue specimens compared with that in paired normal tissue. High HOTTIP expression was positively associated with bad clinicopathologic features, including higher pathologic T stage (p < 0.001), presence of extraprostatic extension (p < 0.001), seminal vesicle invasion (p < 0.001), perineural invasion (p < 0.001), and the tumor involvement of resection margin (p = 0.044). In particular, significantly increased HOTTIP expression was observed in specimens from patients in the high or very high-risk group, according to the 2018 National Comprehensive Cancer Network (NCCN) guidelines (p < 0.001). Also, patients with high HOTTIP expression showed poorer overall survival than those with low expression. In conclusion, we analytically validated the poor prognostic significance of HOTTIP overexpression and its association with bad clinicopathologic features, and present HOTTIP as a potential prognostic biomarker in prostate cancer.

Inter-observer Reproducibility in the Pathologic Diagnosis of Gastric Intraepithelial Neoplasia and Early Carcinoma in Endoscopic Submucosal Dissection Specimens: A Multi-center Study.

PURPOSE: The diagnostic criteria of gastric intraepithelial neoplasia (IEN) are controversial across the world. We investigated how many discrepancies occur in the pathologic diagnosis of IEN and early gastric carcinoma in endoscopic submucosal dissection (ESD) specimens, and evaluated the reasons of the discordance. MATERIALS AND METHODS: We retrospectively reviewed 1,202 ESD specimens that were originally diagnosed as gastric IEN and early carcinoma at 12 institutions. RESULTS: The final consensus diagnosis of carcinoma were 756 cases, which were originally 692 carcinomas (91.5%), 43 high-grade dysplasias (5.7%), 20 low-grade dysplasias (2.6%), and 1 others (0.1%), respectively. High- and low-grade dysplasia were finally made in 63 and 342 cases, respectively. The diagnostic concordance with the consensus diagnosis was the highest for carcinoma (91.5%), followed by low-grade dysplasia (86.3%), others (63.4%) and high-grade dysplasia (50.8%). The general kappa value was 0.83, indicating excellent concordance. The kappa values of individual institutions ranged from 0.74 to 1 and correlated with the proportion of carcinoma cases. The cases revised to a final diagnosis of carcinoma exhibited both architectural abnormalities and cytologic atypia. The main differential points between low- and high-grade dysplasias were the glandular distribution and glandular shape. Additional features such as the glandular axis, surface maturation, nuclear stratification and nuclear polarity were also important. CONCLUSION: The overall concordance of the diagnosis of gastric IEN and early carcinoma in ESD specimens was excellent. It correlated with the proportion of carcinoma cases, demonstrating that the diagnostic criteria for carcinoma are more reproducible than those for dysplasia.

High Yes-associated protein 1 with concomitant negative LATS1/2 expression is associated with poor prognosis of advanced gastric cancer.

The Hippo pathway is a tumour-suppressive pathway and its inactivation is known to be associated with progression and metastasis of various cancers. LATS1/2 (large tumour suppressor homolog 1 and 2), YAP1 (Yes-associated protein 1), and TEAD4 (TEA domain-containing sequence-specific transcription factors 4) are core components of the Hippo pathway, and their prognostic roles have not yet been studied in advanced gastric cancers (AGCs). A total of 318 surgically resected AGCs were retrieved. Immunolabelling for LATS1/2, YAP1 and TEAD4 was compared with clinicopathological factors including patients' survival. High expression of YAP1 and TEAD4 was identified in 108 (34.0%) and 131 (41.2%) cases, respectively, and 223 (70.1%) cases were negative for LATS1/2 expression. High YAP1 expression was significantly correlated with the presence of perineural invasion (p=0.032). High YAP1 and high TEAD4 expressions were significantly associated with poor overall survival (p<0.001 and p=0.003, respectively), and negative LATS1/2 expression was also associated with poor overall survival (p=0.002). Combined expression of YAP1highLATS1/2neg showed the worst overall survival (p<0.001). Expression of YAP1high (HR=2.938; 95% CI 1.726-4.998; p<0.001), LATS1/2neg (HR=0.371; 95% CI 0.181-0.758; p=0.007), and combined YAP1highLATS1/2neg (HR=13.785; 95% CI 3.245-58.554; p<0.001) were independent poor prognostic factors of AGC patients. Combined or individual expression of YAP1, LATS1/2, and TEAD4 can be used as prognostic markers of AGC patients.

Tumor microenvironmental factors have prognostic significances in advanced gastric cancer.

Tumor microenvironment is important in the progression and survival of cancer cells. We evaluated the prognostic significance of tumor stroma percentage (TSP), Klintrup-Mäkinen (KM) grade, which reflects the density of inflammatory cells of the tumor, and Glasgow microenvironment score (GMS), a combination of TSP and KM grade, in advanced gastric cancers. A total of 196 pT3 and pT4 gastric cancers were histologically evaluated using TSP, KM grade, and GMS. These were correlated with other clinicopathologic factors including patients' survival. High TSP (78 cases), low KM grade (124 cases), and higher GMS (score 0, 72 cases; 1, 53 cases; and 2, 71 cases) were correlated with poor differentiation, diffuse type, presence of lymphovascular invasion, perineural invasion, and lymph node metastasis. High TSP was significantly correlated with low KM grade (p < 0.001). High TSP (HR, 3.079, 95% CI, 1.612-5.883, p = 0.001), low KM grade (3.201, 1.774-5.776, p < 0.001), and higher GMS (12.274, 3.684-40.895, p < 0.001) were independent poor prognostic factors. TSP, KM grade, and GMS are significantly associated with clinicopathologic behavior and patients' survival. Assessing these factors is a feasible and cost-effective way to identify tumor microenvironment with different biological features and prognosis of gastric cancer patients.

Combined Adenosquamous and Large Cell Neuroendocrine Carcinoma of the Gallbladder.

Large cell neuroendocrine carcinoma (LCNEC) of the gallbladder is extremely rare and usually combined with other type of malignancy, mostly adenocarcinoma. We report an unusual case of combined adenosquamous carcinoma and LCNEC of the gallbladder in a 54-year-old woman. A radical cholecystectomy specimen revealed a 4.3×4.0 cm polypoid mass in the fundus with infiltration of adjacent liver parenchyma. Microscopically, the tumor consisted of two distinct components. Adenosquamous carcinoma was predominant and abrupt transition from adenocarcinoma to squamous cell carcinoma was observed. LCNEC showed round cells with large, vesicular nuclei, abundant mitotic figures, and occasional pseudorosette formation. The patient received adjuvant chemotherapy. However, multiple liver metastases were identified at 3-month follow-up. Metastatic nodules were composed of LCNEC and squamous cell carcinoma components. Detecting LCNEC component is important in gallbladder cancer, because the tumor may require a different chemotherapy regimen and show early metastasis and poor prognosis.

Tumour infiltrating lymphocytes are predictors of lymph node metastasis in early gastric cancers.

Lymph node metastasis (LNM) is an important factor for predicting prognosis and selecting appropriate treatment in early gastric cancers (EGCs). We investigated the histopathological and microenvironmental predictors of LNM in EGCs. We retrieved 43 cases of EGC without LNM and 59 cases with LNM. Clinicopathological variables and tumour-infiltrating lymphocytes (TILs), Crohn's-like lymphoid reaction (CLR), tumour stromal percentage (TSP), and FOXA1 expression were evaluated and correlated with LNM. Among the 102 cases, 68 cases (66.7%) had low TILs and 34 cases (33.3%) had high TILs. High TILs were significantly correlated with the absence of LNM (p<0.001), less extent of invasion (p=0.004), absence of LVI (p=0.035), conspicuous CLR (p<0.001), and the absence of TSP (p=0.009). Conspicuous CLR was observed in 47 cases (46.1%) and TSP was present in 17 cases (16.7%) and neither was correlated with LNM. High FOXA1 expression was significantly associated with presence of LNM, low TILs, and submucosal invasion. In multivariate analysis, low TILs (p=0.023), LVI (p=0.008), and submucosal invasion (p=0.001) were independent predictive factors for LNM in EGCs. Evaluation of TILs in biopsied or endoscopically resected EGC specimens may help to predict LNM and select subsequent proper treatment modalities and follow-up.

Comparison of the Mismatch Repair System between Primary and Metastatic Colorectal Cancers Using Immunohistochemistry.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignancies worldwide. Approximately 10%-15% of the CRC cases have defective DNA mismatch repair (MMR) genes. Although the high level of microsatellite instability status is a predictor of favorable outcome in primary CRC, little is known about its frequency and importance in secondary CRC. Immunohistochemical staining (IHC) for MMR proteins (e.g., MLH1, MSH2, MSH6, and PMS2) has emerged as a useful technique to complement polymerase chain reaction (PCR) analyses. METHODS: In this study, comparison between the MMR system of primary CRCs and paired liver and lung metastatic lesions was done using IHC and the correlation with clinical outcomes was also examined. RESULTS: Based on IHC, 7/61 primary tumors (11.4%) showed deficient MMR systems, while 13/61 secondary tumors (21.3%) showed deficiencies. In total, 44 cases showed proficient expression in both the primary and metastatic lesions. Three cases showed deficiencies in both the primary and paired metastatic lesions. In 10 cases, proficient expression was found only in the primary lesions, and not in the corresponding metastatic lesions. In four cases, proficient expression was detected in the secondary tumor, but not in the primary tumor. CONCLUSIONS: Although each IHC result and the likely defective genes were not exactly matched between the primary and the metastatic tumors, identical results for primary and metastatic lesions were obtained in 77% of the cases (47/61). These data are in agreement with the previous microsatellite detection studies that used PCR and IHC.

Application of genetically engineered Salmonella typhimurium for interferon-gamma-induced therapy against melanoma.

Salmonella have been experimentally used as anti-cancer agents, because they show selective growth in tumours. In this study, we genetically modified attenuated Salmonella typhimurium to express and secrete interferon-gamma (IFN-γ) as a tumouricidal agent to enhance the therapeutic efficacy of Salmonella. IFN-γ was fused to the N-terminal region (residues 1-160) of SipB (SipB160) for secretion from bacterial cells. Attenuated S. typhimurium expressing recombinant IFN-γ (S. typhimurium (IFN-γ)) invaded the melanoma cells and induced cytotoxicity. Subcutaneous administration of S. typhimurium (IFN-γ) also efficiently inhibited tumour growth and prolonged the survival of C57BL/6 mice bearing B16F10 melanoma compared with administration of phosphate-buffered saline (PBS), unmodified S. typhimurium or S. typhimurium expressing empty vector (S. typhimurium [Vec]) in a natural killer (NK) cell-dependent manner. Moreover, genetically modified Salmonella, including S. typhimurium (IFN-γ), showed little toxicity to normal tissues with no observable adverse effects. However, S. typhimurium (IFN-γ)-mediated tumour suppression was attributed to direct killing of tumour cells rather than to stable anti-tumour immunity. Collectively, these results suggest that tumour-targeted therapy using S. typhimurium (IFN-γ) has potential for melanoma treatment.

Clinicopathologic Characteristics and Mutational Status of Succinate Dehydrogenase Genes in Paraganglioma of the Urinary Bladder: A Multi-Institutional Korean Study.

CONTEXT: - Because of the limited number of available primary bladder paraganglioma (PBPG) cases, the rates of succinate dehydrogenase (SDH) mutations and the clinicopathologic characteristics of SDH-deficient tumors have not been fully studied. OBJECTIVE: - To define the clinicopathologic and molecular characteristics of PBPGs. DESIGN: - A total of 52 PBPGs were collected retrospectively. SDHA and SDHB immunohistochemical stains were performed. In cases of SDHB expression loss, mutation analyses of SDHB, SDHC, and SDHD were performed. RESULTS: - The clinicopathologic features were analyzed for 52 cases (M:F = 27:25), with a mean age of 56 years (range, 22-79 years). Tumor sizes were 0.5 to 8 cm (mean, 2.4 cm). Tumor necrosis was present in 5 of 52 cases (10%), involvement of muscularis propria in 41 (79%), and lymphovascular tumor invasion in 6 (12%). During a mean follow-up period of 41 months (range, 1-161 months), 3 of 52 patients (6%) developed metastases, but no one died from the disease. Immunohistochemistry for SDHA and SDHB showed that all cases were SDHA intact. Among them, 43 cases had intact SDHB, whereas 9 cases were SDHB deficient. Compared with the SDHB-intact cases, the SDHB-deficient cases were characterized by large tumor sizes (4.5 versus 1.9 cm; P < .001), a higher number of mitoses per 10 high-powered fields (2.6 versus 0.1; P = .002), and frequent lymphovascular tumor invasion (33% versus 7%; P = .02) and metastases (22% versus 2%; P = .02). Mutational analyses for SDHB, SDHC, and SDHD were performed in 9 SDHB-deficient cases. Among them, 6 cases were successfully sequenced and revealed SDHB mutations only. CONCLUSIONS: - Large tumor size, a higher number of mitoses, and the presence of lymphovascular tumor invasion and SDHB mutations suggest malignant paraganglioma.

Predicting Extrathyroidal Extension in Patients With Papillary Thyroid Microcarcinoma According to a BRAF Mutation.

OBJECTIVES: The aim of this study was to evaluate the association between preoperative parameters and extrathyroidal extension (ETE) of papillary thyroid microcarcinoma (PTMC) according to the BRAF mutation and to evaluate the preoperative predictability of ETE. METHODS: We analyzed the medical records of 332 patients with PTMC (140 in the BRAF- group and 192 in the BRAF+ group). The presence of ETE was subjected to a correlation analysis with age, sex, tumor size, clinical nodal status, and ultrasonography (US) findings. Among the US findings, the correlation between tumors and the thyroid capsule was categorized into four groups; US group A, intraparechymal; US group B, tumor abutting the capsule <50% of diameter; US group C, tumor abutting >50% of diameter; and US group D, tumor destroyed the capsule. The predictive value of ETE, including sensitivity, specificity, and positive and negative predictive values were evaluated. RESULTS: Tumor size and US group were significantly correlated with gross ETE in the BRAF- and BRAF+ groups. Tumor size of 0.5 cm and US groups B and C in the BRAF- group were cutoff values for gross ETE, with a negative predictive value of 100%, whereas tumor size of 0.7 cm and US groups A and B in the BRAF+ group had negative predictive values of 92.4% and 100%, respectively. CONCLUSION: Excluding of ETE by US was categorized according to tumor size and US findings. A different categorization to exclude ETE is needed according to the BRAF mutation.

Does Polymerase Chain Reaction of Tissue Specimens Aid in the Diagnosis of Tuberculosis?

BACKGROUND: Mycobacterial culture is the gold standard test for diagnosing tuberculosis (TB), but it is time-consuming. Polymerase chain reaction (PCR) is a highly sensitive and specific method that can reduce the time required for diagnosis. The diagnostic efficacy of PCR differs, so this study determined the actual sensitivity of TB-PCR in tissue specimens. METHODS: We retrospectively reviewed 574 cases. The results of the nested PCR of the IS6110 gene, mycobacterial culture, TB-specific antigen-induced interferon-γ release assay (IGRA), acid-fast bacilli (AFB) staining, and histological findings were evaluated. RESULTS: The positivity rates were 17.6% for PCR, 3.3% for the AFB stain, 22.2% for mycobacterial culture, and 55.4% for IGRA. PCR had a low sensitivity (51.1%) and a high specificity (86.3%) based on the culture results of other studies. The sensitivity was higher (65.5%) in cases with necrotizing granuloma but showed the highest sensitivity (66.7%) in those with necrosis only. The concordance rate between the methods indicated that PCR was the best method compared to mycobacterial culture, and the concordance rate increased for the methods using positive result for PCR or histologic features. CONCLUSIONS: PCR of tissue specimens is a good alternative to detect tuberculosis, but it may not be as sensitive as previously suggested. Its reliability may also be influenced by some histological features. Our data showed a higher sensitivity when specimens contained necrosis, which indicated that only specimens with necrosis should be used for PCR to detect tuberculosis.