Liquid-based Preparations Research Articles

Cytologic features of parathyroid fine-needle aspiration on ThinPrep preparations.

Previous studies have provided cytologic criteria that aid in the recognition of parathyroid tissue on aspirate smears, including high cellularity, the presence of naked nuclei, loose 2-dimensional clusters, and papillary architecture. However, to the authors knowledge, the cytomorphologic features of parathyroid fine-needle aspiration (FNA) on liquid-based preparations have not been previously described. The authors retrospectively reviewed all parathyroid FNAs that had aspirate smears and a ThinPrep preparation performed over 10 years at 1 institution. The FNA smears and ThinPrep preparations from each case were deidentified and independently reviewed for cellularity, naked nuclei, architecture, and colloid-like material. Forty patients were included in the current study. When individual cases were compared, the ThinPrep preparation was more likely to have lower cellularity, lack papillary architecture, lack naked nuclei, and have areas with a microfollicular pattern compared with the FNA smear. The cytologic features of parathyroid tissue vary depending on preparation. Many of the common features of parathyroid aspirates are lost on ThinPrep preparations, and an increased percentage of parathyroid FNA specimens have a microfollicular pattern on ThinPrep. This may lead to difficulty in recognizing parathyroid origin on FNA.

Mo1397 Clinical Impact of Liquid-Based or Cell Block Preparation of Residual Material After Analysis of Cytological Smears in Endoscopic Ultrasound-Guided Fine-Needle Aspiration

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is an accurate and safe technique to biopsy lymph nodes and masses for cytological analysis. If residual tissue or lymph node fluid is available after preparation of cytological smears, this can be used for liquid-based or cell block preparation, which may be useful when smears are inadequate and/or additional immunohistochemistry is required. For liquid-based preparation, residual material is placed in hemolytic solution and then placed on a slide, resulting in a thin layer of cells.

Liquid‐based cytologic findings of solitary extramedullary plasmacytoma in thyroid: A case report identified with fine‐needle aspiration cytology

Preoperative cytologic diagnosis of solitary extramedullary plasmacytoma (SEP) presents a challenge to cytopathologists because this tumor rarely occurs as a primary thyroid malignant neoplasm. In this report, we provide the first description of liquid-based cytomorphologic findings of SEP observed on fine-needle aspiration biopsy (FNAB) of the thyroid. A 56-year-old woman with a history of Hashimoto thyroiditis presented with a growing nodule in the thyroid. The liquid-based preparation obtained from FNAB showed numerous dispersed plasmacytoid cells with occasional loosely cohesive aggregates of tumor cells. Cells were round to oval in shape, with eccentrically located nuclei. Hyalinized perinuclear vacuoles were found in the cytoplasm of the tumor cells. Initial cytological findings, including those of immunochemistry using a cell block preparation, were consistent with plasmacytoma. Histopathological examination subsequent to thyroidectomy revealed a plasmacytoma in the thyroid. Plasma cell neoplasms were not concurrently detected in tissues other than the thyroid. On the basis of preoperative FNAB findings, a specific diagnosis of SEP in the thyroid can be difficult because this tumor is rare. Moreover, diagnosis is impeded because SEP in the thyroid resembles other, more common thyroid lesions, including both benign and malignant neoplasms. Careful cytomorphologic examination and supportive studies may be required to fully confirm a diagnosis of SEP.

Reprocessing unsatisfactory ThinPrep papanicolaou tests using a modified SurePath preparation technique.

The frequency of unsatisfactory gynecologic specimens has increased in the study laboratory over the last few years due to the advent of personal lubricants. Similarly, lysed blood, protein, and necrotic debris present a challenge in terms of negative cell transference caused by a clogged filter. In the current study, the authors evaluated the potential use of a modified SurePath reprocessing technique to decrease the frequency of unsatisfactory specimens. An aliquot for human papillomavirus testing was set aside and the remaining specimen in the ThinPrep vial was submitted for sedimentation. A methanol wash was performed using preservative that was added to the remaining sediment. The specimen was vortexed and a protein wash of Tris-buffered deionized water was added before processing. The specimens were stained using the ThinPrep staining protocol. Both the original specimen and the reprocessed specimens were manually reviewed by 1 cytotechnologist and 2 pathologists to determine specimen adequacy. A total of 1937 ThinPrep Papanicolaou tests were reprocessed and examined. Of these, 1093 (56%) specimens were satisfactory, 624 of which (57%) demonstrated evidence of a transformation zone component. Epithelial cell abnormalities were identified in 116 specimens (10.6%), including 11 high-grade squamous intraepithelial lesion specimens (1.0%); 5 specimens with a classification of atypical squamous cells, cannot rule out a high-grade lesion (0.5%); 21 low-grade squamous intraepithelial lesion specimens (1.9%); and 79 specimens classified as atypical squamous cells of undetermined significance (7.2%). The modified SurePath processing technique was adept at handling nearly all of the challenges that biological and environmental conditions (blood, protein, lubricant, etc) present in liquid-based filter preparations. A total of 1093 (56%) of 1937 unsatisfactory ThinPrep Papanicolaou tests were converted to a satisfactory state, resulting in 116 abnormalities (10.6%) being diagnosed that otherwise would have gone undetected

A case of metastatic angiosarcoma diagnosed by liquid-based preparation: peculiar cytoplasmic changes.

Angiosarcoma with predominantly epithelioid features is a rare soft tissue neoplasm and the interpretation of its cytopathologic findings may be difficult. We report a case of metastatic angiosarcoma with predominantly epithelioid features diagnosed by liquid-based cytology. The cytopathologic findings in this case differed from those of the conventional preparation and we found a clean background, no hyperchromatic nuclei and several cytoplasmic changes, including intracytoplasmic vacuoles with peculiar shapes, juxtanuclear condensation and perinuclear clearing. Identification of these changes using liquid-based cytology supplemented with immunochemistry may be helpful in reaching a correct cytopathologic diagnosis.

Screening and dotting virtual slides: A new challenge for cytotechnologists

Digital images are increasingly being used in cytopathology. Whole-slide imaging (WSI) is a digital imaging modality that uses computerized technology to scan and convert entire cytology glass slides into digital images that can be viewed on a digital display using the image viewer software. Digital image acquisition of cytology glass slides has improved significantly over the years due to the use of liquid-based preparations and advances in WSI scanning technology such as automatic multipoint pre-scan focus technology or z-stack scanning technology. Screening cytotechnologists are responsible for every cell that is present on an imaged slide. One of the challenges users have to overcome is to establish a technique to review systematically the entire imaged slide and to dot selected abnormal or significant findings. The scope of this article is to review the current user interface technology available for virtual slide navigation when screening digital slides in cytology. WSI scanner vendors provide tools, built into the image viewer software that allow for a more systematic navigation of the virtual slides, such as auto-panning, keyboard-controlled slide navigation and track map. Annotation tools can improve communication between the screener and the final reviewer or can be used for education. The tracking functionality allows recording of the WSI navigation process and provides a mechanism for confirmation of slide coverage by the screening cytotechnologist as well as a useful tool for quality assurance. As the WSI technology matures, additional features and tools to support navigation of a cytology virtual slide are anticipated.

Asymptomatic hematuria associated with urinary polyomavirus infection in immunocompetent patients

Unlike the case for immunodeficient patients, little is known about polyomavirus (PV) infection in immunocompetent patients. PV infection in immunocompetent individuals has been reported sporadically, but little is known about asymptomatic hematuria. To determine the clinical significance and prevalence of urinary PV infection in immunocompetent patients, a total of 95 individuals admitted to Seoul St. Mary's hospital were investigated. Sixty-four patients were enrolled for evaluation of asymptomatic hematuria, and 31 healthy individuals served as controls. Clinical screening for PV infection was performed by urine cytology analysis by liquid-based preparation and urine RT-PCR for BK virus (BKV) and JC virus (JCV), respectively. The average age of the patients in the PV(+) - and PV(-) -groups with asymptomatic hematuria were 60 years and 46 years, respectively. Urine cytology analysis revealed decoy cells in 37/64 hematuria patients (38.9%), but not in healthy controls. They were more prevalent in male patients. Eighty-two patients (86.3%) had PV viruria, viz., 54/64 patients in the hematuria group and 28/31 in the control group. Interestingly, 28/31 (90.3%) cases in the healthy control group were positive for PV viruria, which exceeded the number in the hematuria group (84.4%). PV viruria was associated primarily with JCV, rather than BKV. PV viruria, including JCV viruria, correlated with urine decoy cells and increased age. In conclusion, urinary PV infection is common in immunocompetent patients with asymptomatic hematuria and is age-related. These data may provide an insight into the pathogenesis and future treatment of asymptomatic hematuria associated with urinary PV infection in immunocompetent patients.

High-risk HPV Testing in the Detection of Cervical Carcinoma using Liquid-based Preparations

High-risk HPV Testing in the Detection of Cervical Carcinoma using Liquid-based Preparations

Transcription Expression and Clinical Significance of mRNA of Vascular Endothelial Growth Factor and Endostatin in Liquid-Based Preparation Specimens from Patients with Cervical Dysplasia and Carcinoma

Objectives: The aim of this study was to assess the diagnostic usefulness of vascular endothelial growth factor (VEGF) and endostatin mRNA in cervical specimens of patients with cervical dysplasia and carcinoma. Study Design: Transcription levels of VEGF and endostatin were detected by RT-PCR in cervical liquid-based preparation specimens and compared with cytological assessments. Results: VEGF as well as endostatin mRNA expression was significantly associated with either cytological or histological diagnosis (p < 0.05). VEGF mRNA and endostatin mRNA were significantly more likely to be expressed in squamous cell carcinomas (SCC) than in cervical intraepithelial neoplasia (CIN) III (p < 0.01 and p < 0.05), and obviously also more likely to be expressed in CINII than in CINI and in CINIII than in CINII (p < 0.05). Eleven inflammation lesions gave positive results by cytology but negative results by RT-PCR for VEGF and endostatin mRNA. Twenty-four SCC lesions gave false-negative or precancerous lesion results by cytology but positive results by RT-PCR for VEGF and/or endostatin mRNA expression. Conclusion: Transcription levels of VEGF and endostatin by RT-PCR may be an adjunct to cytology screening for early detection of cervical carcinomas and may determine the progressive potentiality of individual lesions, especially in high-risk patients.

Formulation and in vivo human bioavailability of dissolving tablets containing a self-nanoemulsifying itraconazole solid dispersion without precipitation in simulated gastrointestinal fluid

To investigate the performance of a solid-state self-nanoemulsifying system with no precipitation in gastric and intestinal fluid, itraconazole (ITZ) was selected as a model drug because of its practically insoluble nature in intestinal fluid. A self-nanoemulsifying ITZ solid dispersion (SNESD) system was prepared as follows: (1) establishment of self-nanoemulsifying composition via the hot melting method, (2) solidification with fumed silicon dioxide (Aerosil 300) via adsorption to prepare SNESD and (3) preparation of a directly compressible tablet containing SNESD. This SNESD was easily formulated in the form of a dissolving tablet and provided a favourable nanoemulsifying microenvironment with no precipitation in the testing media. The SNESD and SNESD-loaded tablet displayed highly enhanced dissolution via nanomisation (266.8nm and 258.3nm at 60min and 120min, respectively), whereas the drug alone or a reference ITZ Sporanox® capsule displayed very low dissolution and precipitated immediately in intestinal fluid. Drug precipitation in intestinal fluid may affect the in vivo performance of poorly soluble weakly basic drugs and was estimated according to the crystal growth theory. The superdisintegrant and surfactant in the formulation of the tablet were very crucial to the dissolution of the SNESD-loaded tablet. The drug contents and dissolution rates of the SNESD-loaded tablets were also stable during storage in terms of dissolution and drug content. The SNESD-loaded tablet displayed significantly increased oral bioavailability in healthy human volunteers compared with the reference Sporanox® capsule. The current solid-state SNESD-loaded tablet could provide an alternative to liquid-based emulsifying preparations for various poorly water-soluble drugs without precipitation in testing media.

PS1-53: Effects of Transitioning from Conventional Methods to Liquid-Based Methods on Unsatisfactory Pap Tests: Results from a Multicenter US Study

Background/Aims Pap testing has transitioned from conventional preparations (CP) to liquid-based preparations (LBP) due to perceived superiority of LBPs. Many studies conclude LBPs reduce unsatisfactory (UNSAT) tests, however some believe the evidence to substantiate this claim is weak. We studied the effect of the transition from CPs to LBPs on the proportion of UNSAT Pap tests (PT) in four health care systems in the United States.

An analysis on the results of thinprep liquid based cytological test in 10 000 patients

Objective By analying 10 000 thinprep liquid based cytological test (TCT) results,we assessed the value of TCT in the diagnosis of cervical disease; and then we explored the rate of concordance between positive cervical cytological interpretation based on liquid-based preparations and subsequent histological diagnosis.Methods The diagnosis of 10 000 patients was made according to the criteria of Bethesda system (TBS),and then compared with the TCT results and the histological diagnosis in the patients with positive results.Results Of the 10 000 patients,561 (5.61％) were abnormal including 18 ASC-H,333 ASCUS,164 LSIL,44 HSIL,one cancer,and one AGC-N.The high-risk of cervical cytology focused on twenty to fifty years,with ASCUS and LSIL mainly in the twenty-years old,ASC-H and HSIL mainly concentrated in the thirty to fifty years old.By comparing with histological diagnosis,LSIL coincidence rate was 71.6％ and HSIL was 77.8％.Conclusions Cervical epithelial lesions have a trend in younger people.TCT has a high agreement with biopsy in positive rate,which suggests that TCT has certain predicative value for pathological results. Key words: Thinprep liquid based cytological test; Histological diagnosis; Coincidence rate

Identification of Trichomonas vaginalis in Different Papanicolaou Test Preparations: Trends Over Time in the College of American Pathologists Educational Interlaboratory Comparison Program

The College of American Pathologists' Interlaboratory Comparison Program in Gynecologic Cytology has seen an increase in enrollment in liquid-based Papanicolaou test challenges with a decrease for conventional Papanicolaou tests. Trichomonas vaginalis can be difficult to identify in all preparation types. To evaluate 20 years of participant results from the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology for Trichomonas to ascertain whether performance has changed because of the introduction of liquid-based Papanicolaou and proficiency testing. Concordance rates for the target diagnosis of Trichomonas vaginalis were evaluated for 167,956 participant responses (1990-2010). A nonlinear mixed model was fit with participant type, preparation type, and a 2-level program year (1990-2005 and 2006-2010) reflecting before and after proficiency testing began. A repeated-measures component allowed modeling of the slide-specific performance to ensure that the overall results were not based on the performance of a few slides. Cytotechnologists had higher concordance with the target diagnosis than did pathologists (89.8% [72,992 of 81,319] versus 83.4% [72,271 of 86,637], P < .001) and better performance for each preparation type (P = .003). Concordance initially dropped after the introduction of proficiency testing (P < .001) for conventional and liquid-based (SurePath) preparations by both participant types, followed by quick, parallel improvement. Performance is high in the detection of Trichomonas vaginalis in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology. Liquid-based Papanicolaou and proficiency testing minimally affected participant performance. Cytotechnologists performed better over time and across preparation types than did pathologists, although pathologists showed performance results parallel to that of the cytotechnologists. Awareness of the performance differences by pathologists and cytotechnologists, as well as their difference in proficiency among liquid-based techniques, may help ensure accurate results in clinical practice.

A Pilot Study Evaluating Liquid-Based Fine Needle Aspiration Cytology of Breast Lesions: A Cytomorphological Comparison of SurePath® Liquid-Based Preparations and Conventional Smears

Objective: Fine needle aspiration cytology (FNAC) is recommended by the World Health Organization as a diagnostic method for breast lesions. The morphological interpretation of liquid-based preparations (LBPs) remains a diagnostic challenge due to considerably altered cytomorphology. The aim of the current study was to compare cytomorphological characteristics of SurePath® (SP)-based LBP and conventional smear (CS) in breast FNACs. Study Design: The study included 77 benign and 60 malignant breast FNACs obtained by both SP and CS, all with tissue confirmation. Cases analyzed with both preparations were reviewed and compared, focusing on 10 cytomorphological features. Results: SP aspirates demonstrated notable cytomorphological alterations. Among them, a prominent three-dimensional configuration of cell clusters and frequent and conspicuous nucleoli were the most prominent characteristics of SP compared with CS. Overall diagnostic performances were comparable but were slightly lower for SP than CS (diagnostic accuracy of two reviewers; 87.6 and 90.5% for SP vs. 91.2 and 92.7% for CS, respectively). Conclusion: Although the reviewer should be aware of distinctive cytomorphological alterations, the SP technique is reliable for the evaluation of breast lesions with the advantage of easy interpretation and a diagnostic accuracy equivalent to CS.

Accuracy and False-Positive Rate of the Cytologic Diagnosis of Follicular Cervicitis: Observations From the College of American Pathologists Pap Educational Program

Follicular cervicitis is usually easily identifiable on Papanicolaou (Pap) tests; however, historically, follicular cervicitis is reported to lead to false-positive diagnoses of epithelial cell abnormalities. To assess participant responses in the College of American Pathologists (CAP) Pap educational program (CAP-PAP) to determine the accuracy and false-positive rate of follicular cervicitis cases. Design.-We performed a retrospective review of 4914 participant responses for gynecologic cytology challenges with the reference diagnosis of follicular cervicitis during 11 years (2000-2010) from CAP-PAP. Reference diagnosis category, false-positive rates by participant type (laboratory, cytotechnologist, pathologist), and preparation type (conventional smears, ThinPrep) were analyzed. Of the total 4914 general category responses, 4368 (88.9%) were benign while 546 (11.1%) responses were epithelial cell abnormalities (false positives). Of benign responses, only 2026 (46.4%) were an exact match to follicular cervicitis. Adenocarcinoma and high-grade squamous intraepithelial lesion were the most common diagnoses chosen as a false-positive interpretation (42.3% and 20.1%, respectively). Participant type was significantly associated with false-positive interpretations (laboratory: 19.2%; cytotechnologist: 11.1%; pathologist: 7.9%; P < .001). ThinPrep was also significantly associated with false-positive results as compared to conventional smears (12.2% versus 3.6%; P < .001). In an interlaboratory comparison educational program, follicular cervicitis is difficult to interpret accurately and represents an important cause of false-positive responses. Follicular cervicitis may mimic adenocarcinoma or high-grade squamous intraepithelial lesion, particularly in liquid-based preparations. The diagnostic difficulty most likely arises from the lymphocytes being less conspicuous in the background as well as their tendency to aggregate in ThinPrep as compared to conventional smears.

Effects of transitioning from conventional methods to liquid‐based methods on unsatisfactory Papanicolaou tests

Papanicolaou (Pap) testing has transitioned from conventional preparations (CPs) to liquid-based preparations (LBPs) because of the perceived superiority of LBPs. Many studies conclude that LBPs reduce unsatisfactory Pap tests; however, some believe that the evidence substantiating this claim is weak. The authors studied the effect of the transition from CPs to LBPs on the proportion of unsatisfactory Pap tests in 4 health care systems in the United States participating in the National Institutes of Health-funded Screening Effectiveness and Research in Community-Based Healthcare (SEARCH) project. The study cohort consisted of 548,174 women ages 21 to 65 years who had 1443,725 total Pap tests between 2000 and 2010. Segmented regression analysis was used to estimate the effect of adopting LBPs on the proportion of unsatisfactory Pap tests after adjusting for age. Three sites that implemented SurePath LBP experienced significant reductions in unsatisfactory Pap tests (estimated effect: site 1, -2.46%; 95% confidence interval [CI], -1.47%, -3.45%; site 2, -1.78%; 95% CI, -1.54%, -2.02%; site 3, -8.25%; 95% CI, -7.33%, -9.17%). The fourth site that implemented ThinPrep LBP did not experience a reduction in unsatisfactory Pap tests. The relative risk of an unsatisfactory Pap test in women aged ≥ 50 years increased after the transition to LBPs (SurePath: relative risk, 2.1; 95% CI, 1.9-2.2; ThinPrep: relative risk, 1.7; 95% CI, 1.5-2.0). The observed changes in the proportion of unsatisfactory Pap tests varied across the participating sites and depended on the type of LBP technology, the age of women, and the rates before the implementation of this technology.

Stability of DNA, RNA, cytomorphology, and immunoantigenicity in Residual ThinPrep® Specimens

The aim of this study was to evaluate the quality of residual liquid-based preparation (LBP) sample after cytopathologic diagnosis. Cervical swab, body fluid, and thyroid fine-needle aspiration (FNA) samples preserved in ThinPrep PreservCyt solution were tested. Samples kept frozen at -80 °C and stored at room temperature were tested 12 months after the initial sample collection. Gel electrophotography of GAPDH multiplex PCR, RNA integrity number (RIN) values obtained from Agilent bioanalyzer, cytomorphologic changes, and immunohistochemical staining (cytokeratin, thyroid transcription factor-1 (TTF-1), and D2-40) were used for the evaluation of sample quality. All available samples showed successful amplification products in multiplex PCR. However, RNAs in all residual samples were degraded with low RIN values (RIN < 4). RIN values decreased rapidly when samples were stored at room temperature in LBP medium. Cytomorpholoic evaluation and immunohistochemical staining results revealed no change regardless of storage time or storage temperature. In conclusion, RNAs stored in LBP medium degraded quickly at room temperature. Residual alcohol-based LBP cytologic specimens stored at -80 °C and room temperature showed no change in DNA quality, cytomorphology, and immunoreactivity during at least one year of storage.

Comparison of liquid-based and conventional preparations in cytologic diagnosis of pancreatobiliary lesions

胰胆管肿瘤由于位置深,取材困难,不易早期诊断.临床通常经内镜逆行胰胆管造影(ERCP)胰胆管刷检进行细胞学诊断.近年来,随着传统的细胞学技术不断改进,全自动液基细胞学检测技术(liquid-based cytology test,LCT)已被广泛应用到宫颈[1]、痰[2]、胸腹腔积液[2]等各个领域,但在胰胆管刷检细胞学诊断中的应用尚少见.我们将LCT技术应用于156例行ERCP胰胆管刷检标本的细胞学诊断,并与传统涂片进行对照,探讨LCT在提高胰胆管细胞学病理诊断的敏感性和准确性中的意义。

The cytology and DNA detection by the PapilloCheck(®) test in the diagnosis of human papillomavirus infection.

The aim of this study was to make a comparison between the results obtained by cytologies and by the detection and genotyping of human papillomavirus (HPV) DNA in the screening of cervical cancer. In this study, there were 994 samples used from human females. These were obtained from liquid-based preparations. The samples were analyzed by cytological technique and by the detection of HPV DNA using the PapilloCheck(®) Test. The HPV was detected in 28% of the samples. Most of the cytology lesions appeared in HPV positive samples and, within these, the most serious injuries occurred mostly in samples with multiple HPV infections. The results indicate that, in general, there is a correlation between the detection of HPV DNA and cytology. However, there were some cases that emphasize the limitations of both diagnosis methods (27% cases with viral HPV DNA positive and normal cytologies and about 2% of cytological lesions detected in samples HPV negatives). It is possible to conclude that none of the two techniques is enough by itself and should be applied together in order to increase the accuracy of cervical cancer screening.

Preparation of DNA from cytological material

Personalized oncology requires molecular analysis of tumor cells. Several studies have demonstrated that cytological material is suitable for DNA analysis, but to the authors' knowledge there are no systematic studies comparing how the yield and quality of extracted DNA is affected by the various techniques used for the preparation of cytological material. DNA yield and quality were compared using cultured human lung cancer cells subjected to different preparation techniques used in routine cytology, including fixation, mounting medium, and staining. The results were compared with the outcome of epidermal growth factor receptor (EGFR) genotyping of 66 clinical cytological samples using the same DNA preparation protocol. All tested protocol combinations resulted in fragment lengths of at least 388 base pairs. The mounting agent EcoMount resulted in higher yields than traditional xylene-based medium. Spray and ethanol fixation resulted in both a higher yield and better DNA quality than air drying. In liquid-based cytology (LBC) methods, CytoLyt solution resulted in a 5-fold higher yield than CytoRich Red. Papanicolaou staining provided twice the yield of hematoxylin and eosin staining in both liquid-based preparations. Genotyping outcome and quality control values from the clinical EGFR genotyping demonstrated a sufficient amount and amplifiability of DNA in both spray-fixed and air-dried cytological samples. Reliable clinical genotyping can be performed using all tested methods. However, in the cell line experiments, spray- or ethanol-fixed, Papanicolaou-stained slides provided the best results in terms of yield and fragment length. In LBC, the DNA recovery efficiency of the preserving medium may differ considerably, which should be taken into consideration when introducing LBC. Cancer (Cancer Cytopathol) 2013;121:344-353. © 2013 American Cancer Society.