Apoptosis in breast cancer

OBJECTIVE: To evaluate apoptotic rates on fine needle aspiration (FNA) samples of infiltrating duct carcinoma of the breast and to determine whether cytologic grading improved with consideration of the apoptotic rate in comparison with histologic grading. STUDY DESIGN: We studied 35 women who underwent mastectomy following an FNA diagnosis of infiltrating ductal carcinoma. Concordance between cytologic and histologic grades was calculated. Next, cytologic grades were considered with the apoptotic rates and compared with the histologic grades. RESULTS: An overall concordance of 82.9% was noted between the cytologic and histologic grading systems, with maximum concordance in grade 1 and minimum in grade 3 breast cancers. A highly significant difference in the apoptotic rates, as calculated on cytology, existed between the three histologic grades, indicating a significant increase in apoptosis with rising histologic grade. Applying multiple regression analysis, a significant improvement of cytologic grade with consideration of the apoptotic rate was observed. CONCLUSION: Employing histologic grade as the yardstick, cytology was less sensitive for the purpose of grading breast ductal carcinoma. However, by considering the apoptotic rates, the sensitivity of cytologic grading significantly rose in relation to histologic grade. Larger studies are required to determine whether apoptosis can be incorporated into the existing cytologic grading systems to increase their sensitivity.     

Cytologic grading and DNA image cytometry of breast carcinoma on fine needle aspiration cytology smears

OBJECTIVE: To correlate the cytologic grade of breast carcinoma with DNA image cytometry (ICM) and nuclear area on fine needle aspiration cytology (FNAC) smears. STUDY DESIGN: In this prospective study, FNAC material from 28 breast carcinomas were studied for cytologic grade and DNA ICM. Breast carcinomas were classified as grade 1-3 (low to high). DNA histograms were classified by the modified Auer method. Degree of hyperploidy (DH), ploidy balance (PB) and nuclear area (NA) were measured on Feulgen-stained smears by a CAS 200 image cytometer. Cytologic grade was correlated with DNA ICM findings and NA. RESULTS: There were 3 cytologic grade 1, 13 grade 2 and 12 grade 3 breast carcinomas. Seven of eight cases of hypertetraploid aneuploidy were grade 3 tumors. All cytologic grade 1 tumors were diploid. There were significant differences in DH, PB and NA in different grades of breast carcinoma (one-way ANOVA). CONCLUSION: DNA image cytometry in combination with cytologic grading might offer additional information for the characterization of breast carcinomas diagnosed by FNAC. These observations are of particular interest with the introduction of preoperative chemotherapy.     

Stereotaxic fine needle aspiration cytology of clinically occult malignant and premalignant breast lesions

Stereotaxic fine needle aspiration (FNA) cytology was used to study clinically occult (nonpalpable) breast lesions in 114 consecutive patients with mammographically suspicious findings prior to excisional biopsy. The aspirate contained insufficient material for cytologic evaluation in 15 cases (13.2%), which were histologically diagnosed as benign (7 cases), atypical hyperplasia (7 cases) or carcinoma in situ (1 case). The cytologic findings indicated a benign lesion in 77 cases (67.5%), which were histologically diagnosed as benign (71 cases) or atypical ductal hyperplasia (6 cases). The cytologic sample showed atypia in eight cases (7.0%), which were histologically diagnosed as severe atypical ductal hyperplasia (three cases), carcinoma in situ (one case) or proliferative fibrocystic disease (four cases). In the eight cases (7.0%) cytologically interpreted as probably malignant, histology confirmed six invasive carcinomas, one carcinoma in situ and one fibrocystic disease. Of six cases (4.4%) cytologically reported as malignant, five were histologically diagnosed as invasive carcinoma and one as carcinoma in situ. Overall, stereotaxic FNA cytology reported as malignant or probably malignant 14 of the 15 cases with a histologic confirmation of malignancy, for a sensitivity of 93.3%. Cytology correctly identified 78 of the 83 histologically negative cases, for a specificity of 94.0%. The 16 cases histologically diagnosed as ductal hyperplasia, which carries a high risk for subsequent malignancy, were studied in detail in an effort to define histologic and cytologic criteria for this entity. Using selected histologic criteria, 11 of these cases were graded as showing mild-to-moderate atypical hyperplasia and 5 as showing severe atypical hyperplasia. Three of the latter cases were similarly identified by an analogous cytologic grading; the other two cases had insufficient cytologic samples. The total results in this series of 114 cases support the use of stereotaxic FNA cytology in the diagnosis of these nonpalpable breast lesions, examples of which are illustrated. In particular, it may help to raise the low specificity yielded by mammography alone, which would represent a significant advance for the patient in terms of the accuracy, expediency and reduced cost of diagnosing these lesions.     

Immunocytochemistry and fluorescence in situ hybridization in HER-2/neu status in cell block preparations

OBJECTIVE: Recent studies have validated the use of cytologic materials to determine HER-2/neu status. Good concordance has been shown between results obtained by immunocytochemistry (ICC), immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) on cytologic and surgical specimens. However, the utility of cytologic cell block material in determining HER-2/neu status has not been reported and is the subject of this study. STUDY DESIGN: HER-2/neu status was determined in 25 cases of primary or metastatic breast carcinoma by IHC and FISH. All cases were formalin-fixed, paraffin-embedded (FPPE) cell block preparations. ICC was performed using monoclonal antibodies TAB250 (Zymed) and CB11 (Novacastra Laboratories). FISH analysis was performed using the PathVysion HER-2 probe kit (Vysis, Inc.). Results of ICC and FISH were compared in each case. RESULTS: Of 25 cases studied, 17 showed no protein overexpression or amplification. Five cases showed protein overexpression and amplification. The remaining 3 cases showed 2+ staining intensity by ICC in 10, 20, and 50% of carcinoma cells, respectively, and all demonstrated lack of amplification. CONCLUSION: Immunocytochemistry performed on FFPE cell block material is a reliable method for determining HER-2/neu status in cytologic specimens. We recommend routine preparation of FFPE cell block material in instances of suspected primary of metastatic breast carcinoma.     

Correlation of immunocytochemical and immunohistochemical determination of estrogen and progesterone receptors in breast cancer

OBJECTIVE: To evaluate prospectively the degree of correlation between immunocytochemical (ICC) and immunohistochemical (IHC) determination of estrogen (ER) and progesterone receptors (PR) in breast cancer. STUDY DESIGN: Fine needle aspiration cytology (FNAC) of 101 primary breast cancers were immunostained for ER and PR. They were compared with similar determinations in formalin-fixed paraffin sections of biopsies from the same patients. In cases of discrepancy, the histologic result was considered the gold standard. RESULTS: For ER a cytohistologic correlation of 94%, with a sensitivity of 96.1% and specificity of 86.9%, was found. For PR the cytohistologic correlation was 71.2%, with a sensitivity of 65.7% and specificity of 83.8%. CONCLUSION: ICC determination of hormone receptors in routinely fixed smears obtained by FNAC is a simple method that correlates adequately with the results of IHC determinations, especially for ER.     

Nuclear image morphometry and cytologic grade of breast carcinoma

OBJECTIVE: To correlate visual cytologic grade with automated nuclear morphometry of carcinoma of the breast. STUDY DESIGN: We randomly selected 24 histologically proven infiltrating ductal carcinomas of the breast and 10 benign breast lesions (fibroadenoma). Hematoxylin-eosin-stained fine needle aspiration cytology (FNAC) smears were selected for both cytologic grade and automated image morphometry. The same hematoxylin-eosin-stained FNAC smears were studied for area, convex area, standard deviation of nuclear area, diameter, perimeter and convex perimeters of nucleus. At least 100 cells from each case were measured with an image cytometer. RESULTS: Mean nuclear area, standard deviation of nuclear area, nuclear diameter, convex area, convex perimeter and perimeter were significantly increased from benign versus grade 1 carcinomas and grade 1 versus grade 2 and 3 carcinomas (one way ANOVA test). However, there was no significant difference in grade 2 versus grade 3 carcinomas. CONCLUSION: Automated image cytometry rapidly and successfully measures various nuclear parameters. The measurement of various nuclear parameters would be helpful in future applications of automated diagnosis and grading of breast carcinomas from cytologic material.     

Membrane connectivity estimated by digital image analysis of HER2 immunohistochemistry is concordant with visual scoring and fluorescence in situ hybridization results: algorithm evaluation on breast cancer tissue microarrays

Because metaplastic carcinoma of the breast encompasses a great variety of histopathology, diagnostic challenges abound, especially within the realm of cytology. The authors compiled and studied an eight-case series comprised of metaplastic breast carcinomas and lesions initially suspicious cytologically for metaplastic carcinoma in order to assess the degree of cytologic-histologic correlation and to identify recurring problematic themes surrounding the cytology-based diagnosis of this neoplasm. The cytologic and histologic slides from eight cases suspicious for metaplastic breast carcinoma diagnosed by fine needle aspiration (FNA) were collected and analyzed through a seven-year retrospective search of case files at our institution. Based on cytologic characteristics, the cases were separated into three groups. Group 1 consisted of three cases presenting with poorly differentiated adenocarcinoma and squamoid components on FNA. Group 2 was composed of two cases that featured a monophasic, malignant ductal cell population on cytology, while the cytologic specimens for the third group of cases presented with a mesenchymal component with or without a malignant glandular constituent. Cytologic-histologic correlation was present in two of three cases demonstrating a mesenchymal component, and there was 100% sensitivity in the cytologic detection of those mesenchymal elements. However, in only one of three cases was there an accurate cytologic diagnosis of metaplastic carcinoma when squamoid changes were present on FNA. Both cases demonstrating only malignant glandular elements on cytologic specimens revealed an additional component of malignant squamous differentiation upon the examination of mastectomy-derived tissue. These results indicate that squamous-like changes identified on FNA should be interpreted with caution and that sampling error remains a problematic recurrence in cytology. Regardless, there appears to be promise concerning the accurate cytologic diagnosis of metaplastic carcinoma when the lesion is characterized by a mesenchymal component. A study implementing a larger case number is essential in determining the significance of these findings.     

Stereologic estimates of volume-weighted mean nuclear volume in aspiration smears of ductal breast carcinoma. Correlation with cytologic grade, tumor size and lymph node status

OBJECTIVE: To estimate cytologic volume-weighted mean nuclear volume and correlate it with other prognostic factors, such as tumor diameter and cytologic grading in relation to nodal infiltration. STUDY DESIGN: The relationships between nodal status and nuclear VV, tumor diameter and cytologic grading, according to the modified Black nuclear grading system, were analyzed on fine needle aspirates of 49 cases of breast cancer by univariate and multivariate logistic regression. RESULTS: Volume-weighted mean nuclear volume (nuclear VV) estimated on fine needle aspiration smears showed a significant correlation with grade of tumor differentiation. CONCLUSION: Stereologic evaluation of nuclear size by nuclear VV is an objective method for the cytologic grading of ductal carcinoma of the breast and has independent prognostic value in relation to nodal status higher than those of tumor diameter and cytologic grade.     

Fine needle aspiration cytology of the breast. Experience at an outpatient breast clinic

OBJECTIVE: To evaluate the accuracy of fine needle aspiration cytology (FNAC) of the breast at our institution and to perform quality assurance. STUDY DESIGN: Two hundred forty-six cases with pathologic confirmation were selected and reviewed. A pathologist performed most of the aspirations at an outpatient breast clinic. We correlated cytologic and histologic findings and evaluated the influence of the size, location, grade, and pathologic subtypes and fibrosis in breast lesions on diagnostic results. RESULTS: The likelihood ratios for malignant, suspicious, atypical, benign and unsatisfactory cytologic diagnoses were 98.71, 5.48, 1.09, 0.07 and 0.55, respectively. The absolute and complete sensitivities for malignant lesions were 64.5% and 90.3%, respectively. The specificity was 71.9%. False negative and positive rates were 4.3% and 0.7%, respectively. The predictive value for a malignant cytologic diagnosis was 98.4%. The rate of unsatisfactory samples was 9.3%. The rate of concordance between cytologic and histologic diagnosis was lower for large and diffusely growing lesions (benign and malignant), for malignancies with abundant fibrosis and of unusual types and for carcinomas of low grade. All axillary and recurrent chest wall lesions were diagnosed cytologically. Cell block sections were useful in a small number of cases. CONCLUSION: Understanding the performance and limitations of FNAC can enhance its value as a diagnostic technique in the management of breast disease.     

Value of the cytologic analysis of fine needle aspiration biopsy specimens in the diagnosis of pancreatic carcinomas

Between 1982 and 1986, 410 preoperative percutaneous fine needle aspiration (FNA) biopsies of the pancreas were performed on 316 patients clinically suspected of having a malignant pancreatic tumor. Of 58 patients with pancreatic carcinomas subsequently confirmed by histologic investigation, the FNA biopsy yielded a cytologically positive diagnosis of carcinoma in 39 cases (67.2%) and suspicious findings in another 5 cases (8.6%). In 14 cases of malignancy (24.1%), the FNA puncture failed to sample material from the tumor; hence, the cytologic evaluation yielded false-negative results. Of 21 patients with inflammatory disorders of the pancreas, cytologically suspicious cells were observed in 5 cases (23.8%); in none of those 5 cases did the histologic examination show any evidence of carcinoma. This indicates that caution should be taken not to cytologically over-diagnose cases of pancreatitis. On the whole, cytology proved to be a valuable method for the diagnosis of pancreatic carcinoma; it provided the highest rate of positive results in comparison with other modern clinical diagnostic methods. Furthermore, cytology may improve the diagnostic results even in those cases with clinically negative or merely suspicious findings. FNA punctures of the pancreas produced no serious complications in this series.     

Fine needle aspiration cytology of primary lymphoid lesions of the orbit: report of four cases

BACKGROUND: The role offine needle aspiration cytology (FNAC) in diagnosis and differentiation of primary orbital lymphoid lesions is debatable, and little literature exists on cytodiagnosis of orbital lymphoid lesions. CASES: Four patients with orbital lesions underwent routine FNAC. In 3 cases, histopathologic examination was performed with immunohistochemistry (IHC). Cytologic features and diag- noses were correlated with histopathologic diagnoses. Two were cytologically diagnosed with low-grade non-Hodgkin lymphoma (NHL) and 2 with pseudolymphoma and inflammatory pseudotumor, respectively. Of the 2 cases of histologically diagnosed NHL, 1 had concordant diagnosis and the other had a jalse negative diagnosis of pseudolymphoma; both showed significant increase in mast cells, with neoplastie lymphoid cells exhibiting a higher N:C ratio and coarser chromatin texture. The case cytologically interpreted as suspicious for NHL was identified as a psetedolymphoma on histology (false positive). The case of inflammatory pseudotumor, in which hiopiy was not peiformned, responded well to corticosteroids, strengthening the cytologic diagnosis. CONCLUSION: FNAC diagnosis and differentiation of benign vs. malignant primacy orbital lymphoid lesions is often difficult. Careful cytologic interpretation with respect to certain subtle cytologic details is needed in minimizing false positive or false negative diagnoses. In difficult situations, IHC using suitable immunomarkers proves highly useful.     

Cytomorphology of the variants of small-cell carcinoma of the lung

Cytologic classification of subtypes of small-cell carcinoma of the lung (SCCL) was retrospectively performed on respiratory material of 90 cases of lung carcinoma cytologically diagnosed as SCCL. Additionally, the cytologic material was reexamined for the presence of variants of SCCL in 68 cases of lung carcinoma whose types had not been conclusively defined by cytology. The type of lung cytology specimens reviewed were sputa, bronchial washings and brushings and fine needle aspirations. The study included review of pretreatment tumor histology, when present, and examination of the ultrastructure of the tumor in selected cases whose type had not been well defined by histology. Subtype recognition depended on the adequacy of the specimens rather than on the type of cytologic material examined. The cytologic subtyping was generally in agreement with the histologic subtyping of the tumor, except for cases in which SCCL was combined with other types of lung carcinoma, where certain discrepancies were noted.     

Grading of ductal breast carcinoma by cytomorphology and image morphometry with histologic correlation

OBJECTIVE: To investigate the relevance of image analysis for grading breast carcinoma. STUDY DESIGN: Twenty-five ductal breast carcinoma cases were chosen randomly from routine fine needle aspiration clinics. The results of cytomorphologic grading and image morphometry were correlated with those of histologic grading. The five image morphometric parameters studied were nuclear diameter, nuclear area, nuclear roundness, nuclear perimeter and grey level to compare with chromatin texture. RESULTS: Cytologic grading alone had a high correlation with histologic grading. The lowest correlation was found in grade 2 tumors. When cytologic grading was supplemented with image morphometric parameters, the correlation was higher than that of cytologic grading alone. CONCLUSION: Cytologic grading has a high correlation with histologic grading. The correlation improves further on supplementation with image morphometric parameters.     

Value of fine needle aspiration cytology of the breast, with an emphasis on the cytodiagnosis of colloid carcinoma.

The fine needle aspiration (FNA) cytologic evaluation of 6,941 lesions of the breast was reviewed, with an emphasis on the cytodiagnosis of colloid carcinoma. The most common benign breast diseases in this series were fibroadenomas, cysts and fibrocystic conditions. All cases with an FNA diagnosis of suspicious were biopsied; a number of these were found to be carcinoma of the breast. In cases with an FNA diagnosis of carcinoma of the breast, a plan of management was immediately adopted on the basis of that diagnosis. Thirteen cases of colloid (mucinous) carcinoma of the breast were diagnosed by FNA cytology; in all, the cytodiagnosis was confirmed by the subsequent histologic diagnosis. The distinctive cytologic criteria that may be useful for making an FNA diagnosis of colloid carcinoma of the breast are discussed, and the FNA differences between the pure and mixed types of colloid carcinoma are noted.     

Robinson cytologic grading in invasive ductal carcinoma of the breast: correlation with E-cadherin and alpha-, beta- and gamma-catenin expression and regional lymph node metastasis

OBJECTIVE: To correlate the cytologic grade of breast carcinoma with the expression of E-cadherin/catenin system molecules and the presence of metastasis in regional lymph nodes. STUDY DESIGN: Aspirate smears were examined together with histologic sections from the corresponding neoplasms taken from 100 patients with invasive ductal carcinoma. In 50 cases, > or = 1 metastatic nodes were identified. Cytologic grading of the smears was performed using the Robinson method. Immunohistochemical expression of E-cadherin and of alpha-, beta- and gamma-catenin was studied. RESULTS: A statistically significant relationship was observed between E-cadherin/catenin expression and cytologic grade (p < 0.0005). This association was particularly relevant to the cell dissociation parameter (p < 0.0005). CONCLUSION: The cytological grade established in preoperative studies may provide relevant information on the aggressiveness of invasive ductal carcinoma and its tendency to produce regional metastasis. This finding could be particularly useful in cases of breast carcinoma in which neoadjuvant therapy is the method of choice.     

Papillary breast lesions diagnosed on cytology. Profile of 65 cases

OBJECTIVE: To analyze the cytologic features of nipple discharge and fine needle aspiration (FNA) cytologic smears from breast lesions reported as showing papillary features and to correlate them with histopathologic features. STUDY DESIGN: The study group consisted of FNA smears and/or nipple discharge smears from 65 breast lesions diagnosed on cytology as duct papilloma, papillary lesion, fibrocystic condition, fibroadenoma, papillary neoplasm or papillary carcinoma. Cytomorphologic features assessed included cellularity, cell pattern (clusters, papillary, 3-dimensionality, etc.) and cell characteristics (monomorphism, pleomorphism, apocrine change, plasmacytoid features). Histological material was available for review and cytohistologic correlation in all cases. RESULTS: Forty-six specimens were FNA smears, and 16 were nipple discharge smears; in 3 cases FNA and nipple discharge cytologic smears were available for review. Cytologic study could predict the presence of a papillary pattern in all neoplasms with pure or focal papillary differentiation. There was an overlap in cytomorphologic features between papillary and nonpapillary benign lesions as well as between benign and malignant papillary neoplasms. Frank blood in the aspirate, cell dissociation and atypia, however, were more frequent in the last. CONCLUSION: Overlap of cytologic features in nonneoplastic and neoplastic benign papillary lesions and between benign and malignant papillary neoplasms necessitates histologic evaluation in all cases diagnosed as papillary on cytology. Since 49.2% of lesions showing papillary features on cytology prove to be malignant, all cases reported as papillary on cytology should be excised urgently for histologic assessment.     

Renal fine needle aspiration cytology

OBJECTIVE: To audit and evaluate the pitfalls in renal fine needle aspiration (FNA) cytology. STUDY DESIGN: A retrospective analysis of 180 renal FNAs from 163 patients, encountered at Canberra Hospital, Australian Capital Territory, between June 1989 and July 1997 was undertaken. The FNA procedures had been performed by radiologists under computed tomography (CT) or ultrasound (US) guidance. The study correlated the FNA results with biopsy findings and clinical outcome. RESULTS: The initial cytologic diagnoses included 84 (47%) benign, 6 (3%) atypical, 7 (4%) suspicious, 70 (39%) malignant and 13 (7%) inadequate. Six of the 13 cytologically inadequate group, on further investigation, had malignant histology. The benign cytologic categories contained 79 benign conditions and 5 cases with a malignant outcome. The atypical cytologic group contained 5 benign and 1 malignant case. All nine cytologically suspicious cases had malignant histology. The cytologically malignant group contained 62 malignant, 7 benign and 1 patient lost to follow-up. The sensitivity was 92.5%, specificity was 91.9%, positive predictive value was 89.9%, negative predictive value was 94.0%, and efficacy of the test was 92.2%. CONCLUSION: Renal FNA can provide an accurate diagnosis in most instances; however, aspiration cytology of the kidney has limitations and pitfalls. Low grade renal cell carcinoma has to be differentiated from oncocytoma, angiomyolipoma, renal infarct and reactive conditions. Renal FNA has a high negative predictive value, which is useful in reassuring patients with radiologically and cytologically benign lesions. Negative FNA does not exclude malignancy in the presence of a radiologic suspicion.     

Robinson cytologic grading of invasive ductal breast carcinoma: correlation with histologic grading and regional lymph node metastasis

OBJECTIVE: To evaluate the importance of cytologic grading of breast carcinoma and its association with histologic grading and the existence of axillary lymph node metastasis. STUDY DESIGN: Aspirates and surgical samples from 100 patients with invasive ductal breast carcinoma not otherwise specified were studied. In 50 patients, > or = 1 metastatic nodes were identified. The cytologic grade was evaluated using the Robinson method and the histologic grade using the Elston modification of the Bloom-Richardson method. A study was undertaken to establish the association between histologic and cytologic grades and to compare the various parameters used to evaluate cytologic grade with the presence of axillary node metastasis. RESULTS: A statistically significant association was observed between cytologic and histologic grades (p < 0.0005) and between cytologic grade and presence of axillary metastasis (p < 0.0005). Similarly, cell dissociation (p < 0.0005), cell uniformity (p = 0.0010) and the appearance of nuclear margins (p < 0.0005) all displayed a positive correlation with regional metastasis. CONCLUSION: Cytologic grade may provide relevant information on the aggressiveness of invasive ductal breast carcinoma and could be a useful parameter to take into consideration when selecting neoadjuvant therapy.     

Aspiration biopsy smear pattern as a predictor of biologic behavior in adenocarcinoma of the breast.

Fine needle aspiration cytology (FNAC) is increasingly used for the initial diagnosis of breast carcinoma, yet few studies have investigated the prognostic importance of cytologic features seen in breast FNAC. We studied the relationship between prognosis and smear morphology in 26 patients with breast carcinoma for whom information from long-term follow-up was available. Specifically, we attempted to correlate nuclear grade and smear pattern with hormonal receptor status, lymph node status, breast recurrence and distant metastasis. In an additional five patients (on whom insufficient follow-up information was available), smear pattern and nuclear grade were correlated with hormonal status. Smears were classified into three patterns: typical (sheets and clusters), individual cell predominant and cluster predominant. The individual cell predominant pattern was associated with an increased incidence of distant metastasis when compared with the other two smear patterns (P less than .05). No statistically significant association was observed between smear pattern and the other factors studied. Nuclear grade 2 (of 3) was also associated with an increased incidence of distant metastasis. However, most grade 2 tumors (10/12) were of the individual cell predominant pattern. Smear pattern classification, along with DNA ploidy analysis and hormone receptor analysis of FNAC-derived material, may yield valuable prognostic information.     

High-throughput molecular analysis from leftover of fine needle aspiration cytology of mammographically detected breast cancer

We investigated whether residual material from diagnostic smears of fine needle aspirations (FNAs) of mammographically detected breast lesions can be successfully used to extract RNA for reliable gene expression analysis. Twenty-eight patients underwent FNA of breast lesions under ultrasonographic guidance. After smearing slides for cytology, residual cells were rinsed with TRIzol to recover RNA. RNA yield ranged from 0.78 to 88.40 μg per sample. FNA leftovers from 23 nonpalpable breast cancers were selected for gene expression profiling using oligonucleotide microarrays. Clusters generated by global expression profiles partitioned samples in well-distinguished subgroups that overlapped with clusters obtained using "biologic scores" (cytohistologic variables) and differed from clusters based on "technical scores" (RNA/complementary RNA/microarray quality). Microarray profiling used to measure the grade of differentiation and estrogen receptor and ERBB2/HER2 status reflected the results obtained by histology and immunohistochemistry. Given that proliferative status in the FNA material is not always assessable, we designed and performed on FNA leftover a multiprobe genomic signature for proliferation genes that strongly correlated with the Ki67 index examined on histologic material. These findings show that cells residual to cytologic smears of FNA are suitable for obtaining high-quality RNA for high-throughput analysis even when taken from small nonpalpable breast lesions.