Assessment of clonal relationships in ipsilateral and bilateral multiple breast carcinomas by comparative genomic hybridisation and hierarchical clustering analysis

The issue of whether multiple, ipsilateral or bilateral, breast carcinomas represent multiple primary tumours or dissemination of a single carcinomatous process has been difficult to resolve, especially for individual patients. We have addressed the problem by comparative genomic hybridisation analysis of 26 tumours from 12 breast cancer patients with multiple ipsilateral and/or bilateral carcinoma lesions. Genomic imbalances were detected in 25 of the 26 (96%) tumours. Using the genomic imbalances detected in these 26 lesions as well as those previously found by us in an independent series of 35 unifocal breast carcinomas, we compared a probabilistic model for likelihood of independence with unsupervised hierarchical clustering methodologies to determine the clonal relatedness of multiple tumours in breast cancer patients. We conclude that CGH analysis of multiple breast carcinomas followed by unsupervised hierarchical clustering of the genomic imbalances is more reliable than previous criteria to determine the tumours’ clonal relationship in individual patients, that most ipsilateral breast carcinomas arise through intramammary spreading of a single breast cancer, and that most patients with bilateral breast carcinomas have two different diseases.

CRD-BP: a c-Myc mRNA stabilizing protein with an oncofetal pattern of expression

The Coding Region Determinant-Binding Protein (CRD-BP) is an RRM and KH-domain-containing protein that recognizes specifically at least three RNAs. It binds to one of the two c-myc mRNA instability elements, to the 5'Un Translated Region (UTR) of the leader 3 IGF-II mRNA and to the oncofetal H19 RNA. CRD-BP has been assigned a role in stabilizing c-myc mRNA by preventing its endonucleolytic cleavage and in repressing the translation of the leader 3 IGF-II mRNA, the major embryonic species of this message. CRD-BP is normally expressed only in fetal tissues. However, its expression is detected in primary tumors and transformed cell lines of different origins. The vast majority of colon (80%) and breast (60%) tumors and sarcomas (73%) express CRD-BP whereas in other tumor types, for example prostate carcinomas, its expression is rare. CRD-BP expression has also been detected in benign tumors such as breast fibroadenomas, meningiomas and other benign mesenchymal tumors, implying a role for this gene in abnormal cell proliferation. In breast carcinomas, CRD-BP expression and or gene copy number gains in the region encompassing the c-myc locus were detected in approximately 75% of tumors, implying that the deregulated expression of c-myc may be more widespread than previously believed. Infiltrated lymph nodes, corresponding to CRD-BP-positive primary tumors, were also found positive indicating that monitoring for CRD-BP could prove useful for the detection and monitoring of disseminated disease.

Post-transplant lymphoproliferative syndrome in the pediatric liver transplant population

Post-transplant lymphoproliferative disease remains a complication with a high morbidity and mortality. The present study examined 291 pediatric liver transplants performed in 263 children from October 1984 to December 1999. Post-transplant lymphoproliferative disease has an overall incidence of 12%. Tacrolimus and cyclosporine had a similar incidence of post-transplant lymphoproliferative disease. Fifty-six per cent of patients who developed post-transplant lymphoproliferative disease were Epstein-Barr virus negative at the time of transplantation. Mean time of conversion to Epstein-Barr virus positivity was 1.1 years after liver transplantation. Ten per cent of those who developed post-transplant lymphoproliferative disease never had Epstein-Barr virus detected. Mean time from Epstein-Barr virus positivity to detection of post-transplant lymphoproliferative disease was 2.68 years, and 3.13 years from liver transplantation (OLTx) to post-transplant lymphoproliferative disease. There was a 35% incidence of mortality. Deaths occurred a mean of 0.76 years after diagnosis of post-transplant lymphoproliferative disease. Most cases of post-transplant lymphoproliferative disease had extranodal location. There was one recurrence in 10% of patients, and two in 3%. All recurrent cases were seen in recipients who became Epstein-Barr virus positive after transplantation. There has been a decrease in the incidence of post-transplant lymphoproliferative disease from 15% to 9% to 4%. Post-transplant lymphoproliferative disease should be diagnosed promptly and treated aggressively. The best treatment, however, seems to be prevention, starting in the immediate postoperative period. Survivors should be monitored for both recurrence of post-transplant lymphoproliferative disease and acute cellular rejection.

Evaluation of breast cancer polyclonality by combined chromosome banding and comparative genomic hybridization analysis

Cytogenetically unrelated clones have been detected by chromosome banding analysis in many breast carcinomas. Because these karyotypic studies were performed on short-term cultured samples, it may be argued that in vitro selection occurred or that small clones may have arisen during culturing. To address this issue, we analyzed 37 breast carcinomas by G-banding and comparative genomic hybridization (CGH), a fluorescent in situ hybridization--based screening technique that does not require culturing or tumor metaphases. All but two of the 37 karyotypically abnormal cases presented copy number changes by CGH. The picture of genomic alterations revealed by the two techniques overlapped only partly. Sometimes the CGH analysis revealed genomic imbalances that belonged to cell populations not picked up by the cytogenetic analysis and in other cases, especially when the karyotypes had many markers and chromosomes with additional material of unknown origin, CGH gave a more reliable overall picture of the copy number gains and losses. However, besides sometimes revealing cell populations with balanced chromosome aberrations or unbalanced changes that nevertheless remained undetected by CGH, G-banding analysis was essential to understand how the genomic imbalances arose in the many cases in which both techniques detected the same clonal abnormalities. Furthermore, because CGH pictures only imbalances present in a significant proportion of the test sample, the very detection by this technique of imbalances belonging to apparently small, cytogenetically unrelated clones of cells proves that these clones must have been present in vivo. This constitutes compelling evidence that the cytogenetic polyclonality observed after short-term culturing of breast carcinomas is not an artifact.

Carcinoma in situ of the female breast. 10 year follow-up results of a prospective nationwide study

In a Danish nationwide prospective study of in situ carcinoma of the breast, a total of 275 women, treated with excision alone, were registered from 1982 to 1989. The series included 142 cases of ductal carcinoma in situ (DCIS), 100 cases of lobular carcinoma in situ (LCIS), 26 cases of DCIS+LCIS, and seven cases of atypical hyperplasia (AH). Within a median follow-up of 120 months, a crude recurrence rate of 28% (76 cases) was found, of which 53% (40 cases) recurred as invasive carcinomas (IC) and 47% (36 cases) as CIS. CIS recurrences appeared after median 18 months, compared to median 42 months for IC recurrences. No statistical difference was found with respect to development of IC between the three groups of DCIS, DCIS+LCIS, and LCIS. The majority of recurrences were ipsilateral, also for LCIS. Forty four of 49 recurrences following DCIS, and seven of nine recurrences following DCIS+LCIS occurred as local recurrences. Histopathologically, in DCIS a strong association was found between large nuclear size and comedonecrosis. Univariate analysis showed a significant association to recurrence for nuclear size, comedonecrosis, and size of the original lesion. Multivariate analysis showed that only comedonecrosis and size of lesion were independent predictors of recurrence, however, specimen margins were not included in the analysis, as this parameter could not be adequately evaluated in the present series. Nuclear size of original DCIS lesion was related to histologic grade of the IC recurrence. The recurrence rate for DCIS of small nuclear size increased from 6% at five years of follow-up to 16% at 10 years, possibly due to a slower growth rate and a continued but delayed risk. Similarities were found between LCIS and DCIS of small nuclear size, both showing a continued risk and comparable rate of recurrence. Further, progression to IC of similar, highly differentiated type was seen, indicating a linkage between biological behavior of the two histological types.

Karyotypic evolution in breast carcinomas with i(1)(q10) and der(1;16)(q10;p10) as the primary chromosome abnormality

The pattern of clonal karyotypic evolution in breast carcinomas carrying an i(1q) or a der(1;16)(q10;p10) as the primary chromosome abnormality was assessed in a series of 42 tumors, including 8 described here for the first time, with either or both (3 tumors) of them defining cytogenetic features. Evidence of clonal evolution was seen in somewhat more than half of all cases in both subgroups. The secondarily acquired aberrations appeared to be nonrandom in distribution. This was especially so for structural rearrangements of 11q leading to loss of material from this arm, which were clearly more common in both subgroups than in karyotypically abnormal breast carcinomas in general. Other deviations from random were less certain but seemed to include the frequent occurrence of +20 in tumors with i(1q) and +7 in tumors with der(1;16)(q10;p10). That differences were observed between i(1q) carcinomas and der(1;16)(q10;p10) carcinomas with regard to their patterns of clonal evolution hints that the pathogenetic effect of the primary change in these two situations may be more than the mere gain of an extra copy of 1q.

The importance of surgery and accurate axillary staging for survival in breast cancer

AIMS

The purpose of this study was to investigate, within the context of the Danish Breast Cancer Cooperative Group (DBCG) programmes, whether a dedicated surgical approach had a significant bearing on the outcome of breast cancer treatment.

METHODS

From 1 January 1980 to 31 December 1990, patients below 70 years of age with operable breast cancer from Odense University Hospital (n=743) were compared with those from the rest of Denmark (denoted rest-DK) (n=15,419). All patients were treated according to nationwide DBCG guidelines and reported to the DBCG Data Centre. The potential median observation time was 11.2 years (range 6.0-16.9). Patients underwent mastectomy or breast conserving therapy, and high risk lymph-node positive patients had adjuvant systemic therapy with or without radiotherapy.

RESULTS

Comparing total patients series, overall survival (OS) was significantly superior in patients from Odense compared with rest-DK (P=0.02), with 10-year OSs of 62% (95% CI: 58-65%) and 56% (55-57%), respectively. In subgroups, the OS of low-risk node negative patients (protocol A) in Odense compared with rest-DK was significantly better (P=0.02); 10-year OS was 78% (73-84%) versus 72% (70-73%). Among the high-risk pre-menopausal patients (protocol B), the OS was significantly better in Odense (P=0.009); 10-year OS was 67% (60-75%) versus 53% (51-55%) in rest-DK. Post-menopausal high-risk patients (protocol C) did not differ significantly in OS between Odense and rest-DK (P=0.61). Locoregional control in the Odense series was superior compared with rest-DK. More lymph nodes were recovered and examined from the axilla in the Odense series than in rest-DK, a median of 10 vs. 6 nodes. In the Odense series, a significantly higher proportion of pre-menopausal patients had positive lymph nodes, predominantly one to three positive nodes, and subsequently a lower proportion of pre-menopausal patients had negative lymph nodes compared with rest-DK (P=0.02), indicating a more accurate staging in Odense vs. rest-DK. The survival benefit among the patients from Odense cannot be explained by stage migration alone, but seems to represent a true survival advantage. Overall mortality was significantly lower in the Odense series compared with rest-DK. Whether or not this difference could be explained by lower background mortality in the Odense series or was caused by superior treatment is discussed.

CONCLUSIONS

The extent of surgery seems important for locoregional tumour control and accurate axillary lymph-node staging. In combination, these might lead to superior recurrence-free and overall survival, although differences in background mortality cannot be ignored. Surgery, therefore, might represent a risk factor by itself.

Cytogenetic comparison of primary tumors and lymph node metastases in breast cancer patients

Chromosome banding analysis of primary tumors and axillary lymph node metastases from 10 breast cancer patients revealed abnormal karyotypes in all samples with cytogenetic similarities between the primary tumor and the metastasis in all informative pairs. Although karyotypically unrelated clones were also found in the lymph node samples, they were less numerous than in the primary tumors, indicating that there was more genetic heterogeneity among the neoplastic cells in the primary than in the secondary tumors. On the other hand, some of the clones had become more complex in the metastases as a result of clonal evolution, and by and large these metastatic breast cancer cases had more karyotypic anomalies than do unselected primary breast carcinomas. Among the aberrations occurring more frequently, and that consequently may predispose to disease spread, were losses of chromosomes 17 and 22 and homogeneously staining regions, a cytogenetic sign of gene amplification.

Prognostic significance of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 in primary breast cancer

The uPA-mediated pathway of plasminogen activation is central to cancer metastasis. Whether uPA and PAI-1 are related to local recurrence, metastatic spread or both is not clear. We present a retrospective study of 429 primary breast cancer patients with a median follow-up of 5.1 years, in which the levels of uPA and PAI-1 in tumour extracts were analysed by means of an enzyme-linked immunosorbent assay. The median values of uPA and PAI-1, which were used as cut-off points, were 4.5 and 11.1 ng mg(-1) protein respectively. The levels of uPA and PAI-1 were correlated with tumour size, degree of anaplasia, steroid receptor status and number of positive nodes. Patients with high content of either uPA or PAI-1 had increased risk of relapse and death. We demonstrated an independent ability of PAI-1 to predict distant metastasis (relative risk 1.7, confidence limits 1.22 and 2.46) and that neither uPA nor PAI-1 provided any information regarding local recurrence.

[Penicillin prophylaxis in complicated wounds of hands and feet. A randomized, double-blind study]

Five hundred and ninety-nine patients with traumatic wounds of hands or feet with underlying lesions of the bone, tendon or joint, were randomized to double blind treatment with either A) one injection of penicillin, B) penicillin tablets for six days or C) no antibiotic treatment. In group A the infection rate was 4.9%, in group B it was 6.6% and in group C 10.2%. The difference between the infection rates in group A and C was 5.3% with a 95% confidence interval (CI) from 0.1 to 10.4%, (p = 0.046). Correction for an interim analysis and subgroup analysis increases this p-value to 0.096. The difference between the infection rates in group B and C was 3.6% (95%, CI from -1.9 to 8.9%, p = 0.20). Patients in group B had gastrointestinal complaints five times as often as patients in group A and C. Based on the results we advise that a single prophylactic injection of penicillin is given to patients with these injuries.

Cytogenetic findings in phyllodes tumors of the breast: karyotypic complexity differentiates between malignant and benign tumors

Clonal karyotypic abnormalities were detected in short-term cell cultures from six phyllodes tumors of the breast. Whereas all five benign tumors had simple chromosomal changes, the highly malignant one had a near-triploid stemline, indicating that karyotypic complexity is a marker of malignancy in phyllodes tumors. Interstitial deletions of the short arm of chromosome 3, del(3)(p12p14) and del(3)(p21p23),were the only aberrations in two benign tumors. Cytogenetic polyclonality was detected in three benign tumors: two had cytogenetically unrelated clones, whereas the third had three different, karyotypically related cell populations as evidence of clonal evolution. The finding of clonal chromosome abnormalities in both the epithelial and connective tissue components of the phyllodes tumors indicates that they are genuinely biphasic, that is, that both components are part of the neoplastic parenchyma.

DNA ploidy analysis in breast carcinoma. Comparison of unfixed and fixed tissue analyzed by image and flow cytometry

OBJECTIVE

To form a methodologic basis for DNA analysis of ductal carcinoma in situ (DCIS) and invasive carcinoma (IC) of the breast, including very small lesions, by comparison of flow cytometric (FCM) and image cytometric (ICM) methods for DNA quantitation.

STUDY DESIGN

The material consisted of 41 DCIS lesions and 26 ICs. FCM DNA analysis of unfixed, frozen samples were compared to (1) FCM of formalin-fixed, paraffin-embedded tissue; (2) ICM of imprints; and (3) ICM of paraffin-embedded tissue sections.

RESULTS

FCM of unfixed tissue showed higher DNA measurement precision and a higher number of DNA nondiploid clones as compared to the other three methods. For the classification of DNA diploid/nondiploid cases, high concordance rates were found between the methods. Discordant cases were predominantly DNA neardiploid by FCM of unfixed tissue but DNA diploid by the other methods. The reproducibility of the DNA index (DI) was best in the interval 1.2 < DI < or = 2.2; it was 74% for FCM of fixed tissue and 79% for ICM of imprints. Clones with DI > 3 were found almost exclusively by ICM of imprints. For ICM of tissue sections, DI could not be reliably estimated. By ICM, contrary to FCM, a combined DNA diploid and nondiploid pattern was found frequently.

CONCLUSION

Each of the methods has its own advantages and limitations. If possible, FCM should be combined with ICM. FCM of unfixed tissue is superior to the other methods with respect to precise DI estimation. Alternatively, FCM of fixed tissue and ICM of imprints may both give a reliable estimate of DI. ICM of tissue sections can discriminate DNA diploid from nondiploid clones, except for neardiploid subpopulations, and permits the analysis of very small lesions.

Discrimination between multicentric and multifocal breast carcinoma by cytogenetic investigation of macroscopically distinct ipsilateral lesions

Whether macroscopically distinct carcinomas in the same breast are clonally related (multifocal breast carcinoma) or unrelated (multicentric breast carcinoma) is no longer only a scientific-pathological issue but, because different therapeutic strategies may be preferable for cases with intramammary metastatic disease compared with cases of multiple primary breast carcinomas, one that may have profound clinical implications. We studied the evolutionary relationship among macroscopically distinct, ipsilateral breast carcinomas by cytogenetic analysis of 26 tumorous lesions from 12 patients. Sixteen of the 26 foci (62%) were found to contain clonal chromosome abnormalities. Two carcinoma foci were karyotypically abnormal in each of seven patients. Four of these cases had an evolutionarily related, cytogenetically abnormal clone in the two lesions from the same breast, whereas the remaining three cases had completely different clonal karyotypic aberrations in the separate foci. These results, together with our previous findings in five other informative cases, show that multiple, synchronous breast tumors sometimes arise through intramammary spreading of a single primary carcinoma, whereas on other occasions they are the result of the simultaneous emergence of pathogenetically independent carcinomas within the breast. In the total material, an association was seen between the proximity of the foci and the likelihood of them being karyotypically related.

[Transplantation of human primary in-situ and invasive breast carcinoma in nude mice]

In order to establish nude mice model of early and advanced breast cancers, 15 in-situ breast carcinomas and 31 invasive breast carcinomoas were transplanted in 155 nude mice subcutaneously. A slow-release pellet of 17-beta estradiol was also implanted subcutaneously. During ten months of observation, the in-situ breast cancer tissue eventually did not grow. Light microscopy showed that the implants kept the structure of in-situ carcinoma without invasion. Of 31 invasive carcinomas, only one diagnosed pathologically as multifocal dedifferentiated ductal carcinoma grew well and was serially passaged. It was estrogen- and progesterone-receptor negative, p53 protein negative and c-erbB-2 protein positive. Its DNA ploidy was near tetraploidy.

Cytogenetic abnormalities in an in situ ductal carcinoma and five prophylactically removed breasts from members of a family with hereditary breast cancer

Short-term cultures of tissue samples from three bilateral prophylactic mastectomies and one in situ ductal carcinoma from four women belonging to a family with hereditary breast cancer were cytogenetically analyzed. Clonal chromosome abnormalities were detected in five of the six prophylactically removed breasts, all of which had the histologic diagnosis epithelial hyperplasia without atypia, and in the in situ carcinoma. The same karyotypic imbalance, a loss of 3p12-14, was detected in the in situ carcinoma as well as in one of the hyperplasias, indicating that these bands may harbor a pathogenetically relevant gene in this breast cancer family. The finding of chromosome aberrations in clonal proportions in the prophylactically removed breasts indicates that a neoplastic process was already present, lending support to the view that prophylactic bilateral mastectomy in these high-risk individuals prevented the development of breast carcinoma.

Immunohistochemical localization of urokinase-type plasminogen activator, type-1 plasminogen-activator inhibitor, urokinase receptor and alpha(2)-macroglobulin receptor in human breast carcinomas

We have investigated the localization of urokinase-type plasminogen activator (u-PA), type-1 plasminogen-activator inhibitor (PAI-1), u-PA receptor (u-PAR) and alpha(2)-macroglobulin- receptor/low-density-lipoprotein-receptor-related protein (alpha(2)MR/LRP) in human breast tumors by immunohistochemical methods. Frozen sections of 133 primary breast carcinomas, 6 ductal carcinomas in situ and 33 lymph-node metastases were stained with monoclonal antibodies. Formalin-fixed sections of 15 primary tumors and 2 lymph-node metastases were stained with polyclonal antibodies. In primary tumors, u-PA and PAI-1 immunoreactivities were intense in macrophages and mast cells, and moderate in benign and malignant epithelial cells as well as in myofibroblasts and endothelial cells. A sub-group of poorly differentiated tumors showed particularly strong staining of stromal fibroblasts. u-PA immunoreactivity was also present in lymphocytes. alpha(2)MR/LRP and u-PAR immunoreactivities were intense in macrophages, but apart from these cells, alpha(2)MR/LRP was found only in fibroblasts, and u-PAR only in tumor cells located peripherally in tumor-cell clusters and glands and some myofibroblasts in the adjacent stroma. Lymph-node metastases showed staining for u-PA and PAI-1 both of cancer cells and of stromal fibroblasts, also staining for u-PA of lymphocytes. Similarly to some of the poorly differentiated primary tumors, approximately half of the metastases showed very strong staining of stromal fibroblasts, and extracts of these metastases had higher u-PA and PAI-1 levels, as determined by ELISA, than extracts of metastases without this staining pattern. alpha(2)MR/LRP was present only in fibroblasts and u-PAR only in some tumor cells. The presence of u-PA, PAI-1, alpha(2)MR/LRP and u-PAR was controlled biochemically by immunoblotting analyses, ligand-blotting analyses, and direct and reverse zymography. The spatial distribution and the variation in concentration of the various components of the plasminogen-activation system point to a complex, multifunctional role for the 4 proteins in and/or during the development and spread of breast cancer.

Penicillin prophylaxis in complicated wounds of hands and feet: a randomized, double-blind trial

The purpose of the study was to examine the effect of prophylactic penicillin treatment on the infection rate in patients with traumatic wounds of hands or feet with underlying lesions of bone, tendon or joint. A total of 599 patients were randomized to double-blind treatment with either (A) one injection of penicillin G, (B) penicillin V tablets for 6 days or (C) no antibiotic treatment. In group A the infection rate was 4.9 per cent, in group B 6.7 per cent and in group C 10.2 per cent. The difference between the infection rates in group A and C was 5.3 per cent with a 95 per cent confidence interval (CI) from 0.1 to 10.4 per cent (P = 0.046). Correction for an interim analysis and subgroup analyses increases this P value to 0.096. The difference between the infection rates in group B and C was 3.6 per cent (95 per cent CI from -1.9 to 8.9, P = 0.20). Patients in group B had gastrointestinal complaints five times as often as patients in group A and C. Prophylactic tablets for 6 days require patients' co-operation while an injection ensures that the prophylaxis is given. We therefore conclude that a single prophylactic injection of two million units of penicillin G is advisable for patients with these injuries.

Ectopic pregnancy: histopathology and assessment of cell proliferation with and without methotrexate treatment

OBJECTIVE

To evaluate tubal morphology, trophoblast proliferation, and inflammatory reaction in response to methotrexate (MTX) treatment of ectopic pregnancy (EP).

DESIGN

Nonrandomized controlled study.

SETTING

Academic hospital.

PATIENTS

Archival specimens from 10 EP unsuccessfully treated with MTX and 10 cases primarily treated by surgery.

INTERVENTIONS

Ki67/hCG and Ki67/human placental lactogen double immunohistochemical methods were used to examine trophoblastic spread, placentation, hormone production, decidualization, vascular invasion, hemorrhage, rupture, and proliferative index of the cytotrophoblast. B and T-lymphocyte responses were evaluated by CD3 and CD20.

RESULTS

Trophoblastic spread and placentation were confined to the tubal mucosa after MTX treatment, whereas invasion of the muscularis and subserosa was common in the controls. The proliferative index was reduced (19 percent versus 93 percent), although a high proliferative index was found in two of three cases complicated by rupture. Polar proliferation of Ki67-positive cytotrophoblast toward the implantation site was abolished in MTX-treated cases. Decidual reaction was not observed. No correlation was observed between the above-mentioned findings and gestational age, level of beta-hCG, dose of MTX, or interval to surgery.

CONCLUSION

Trophoblastic spread, differentiation, and invasion were compromised by MTX treatment. Methotrexate seems to decrease cytotrophoblast proliferation. Whether a missing decrease in proliferation index reflects treatment failure awaits a larger population-based study.

Tissue disaggregation for flow cytometric DNA analysis: comparison of fine-needle aspiration and an automated mechanical procedure

Flow cytometric DNA analysis was performed on unfixed frozen samples from 56 breast cancer patients. From each patient, two samples were analyzed. The only difference in the handling of the paired samples was the mechanical disaggregation of one sample by fine-needle aspiration compared to an automated mechanical disaggregation method (Medimachine) of the other sample. With the two methods for tissue disaggregation, the same resolution of the DNA histograms was obtained, indicated by median coefficients of variation (CV) of 1.5% for the DNA diploid G1 peaks. Also, the frequencies of DNA diploid and aneuploid cases as well as the fractions of DNA aneuploid cells were comparable. This indicates that the two methods did not differ in ability to detect DNA aneuploid tumor clones. Automated mechanical disaggregation resulted in DNA histograms with significantly less debris and with lower S-phase fractions. In practice, the procedure of automated mechanical disaggregation was rapid, easy, and safer because of minimal handling of the unfixed tissue compared to the fine-needle aspiration.

Karyotypic comparisons of multiple tumorous and macroscopically normal surrounding tissue samples from patients with breast cancer

Many tumor tissues are made up of genetically different cell populations, and the study of the causes and consequences of this heterogeneity must play a central role in cancer research. We have studied breast cancer clonal heterogeneity by cytogenetic analysis of 4123 cells from 52 successfully short-term-cultured tumorous, metastatic, and macroscopically normal breast tissue samples from 6 women with this disease. All 7 carcinomas (one woman had bilateral disease) contained 1 to 9 karyotypically related as well as unrelated clones, unevenly distributed among the tumor quadrants. Two clonal chromosome abnormalities were recurrent: interstitial 3p deletions were found in 5 carcinomas, whereas del(1)(q42) was detected in another 2 tumors. Both successfully analyzed metastatic lesions (one axillary lymph node and one metastasis in the subcutis) contained only one of several clones present in the primary tumor, thus exemplifying a reduction in overall karyotypic complexity during carcinoma spreading. In the case with the cytogenetically abnormal lymph node, another karyotypically unrelated clone was found to invade locally in the surrounding breast; also, histological evidence of carcinoma infiltration was seen in these tissue samples. In none of the other cases were clonal karyotypic changes found in macroscopically normal, extratumorous breast tissue. We conclude that a large proportion of breast carcinomas are polyclonal with cytogenetically distinct cell subpopulations expanding within separate domains of the growing tumor. Karyotypically disparate neoplastic cells may have different capacities to display malignancy-specific features (e.g., to grow invasively and set up distant metastases). It is presumed that their synergetic action is required for the full-blown carcinoma phenotype.

DNA aneuploidy in early breast cancer

High-resolution flow cytometric (FCM) DNA analysis was performed on 148 unfixed, frozen tissue samples from four groups of early breast cancers: invasive carcinomas (ICs) with predominance of carcinoma in situ (DCIS) (group I), small clinical cancers < or = 15 mm (group II), node-negative, clinical cancers (group III) and small screening-detected cancers < or = 15 mm (group IV). The median tumour size was 12 mm. The aim of the study was to support, with a larger sample, our recent findings with respect to DNA ploidy pattern in the selected group of ICs with predominance of DCIS (group I). Similar results to this group were found for both the small clinical cancers and the node-negative cancers, with respect to frequency of DNA aneuploidy (79% and 90%), DNA index (DI) distribution, intratumoral DNA heterogeneity and S-phase fraction. A high frequency of DNA hyperdiploid clones was found, in particular related to highly differentiated tumours. A significant difference was found compared with the screening-detected cancers, which were characterised by a much lower frequency of DNA aneuploid samples (49%) and may represent a biologically specific group of low-malignant, slowly growing tumours. Associations were shown between histological grade and DI subclasses, and between lymph node status and DNA diploidy/aneuploidy, whereas DI was not correlated with tumour size. The DNA ploidy findings in this series of early cancers are concordant to our own results from preinvasive lesions as well as those reported from series of more advanced cancers.

Clonal heterogeneity in breast cancer: karyotypic comparisons of multiple intra- and extra-tumorous samples from 3 patients

Intratumor phenotypic heterogeneity is one of the characteristics of breast carcinomas, and genetic mechanisms are likely to contribute to it. We have studied breast cancer clonal heterogeneity by cytogenetic analysis of multiple tumor samples (one from each tumor quadrant) as well as samples of macroscopically normal surrounding breast tissue from 3 patients with this disease. Clonal chromosome aberrations were found in all 8 successfully analyzed samples from the carcinomas. Two to 6 cytogenetically unrelated clones were detected in each case, unevenly distributed among the tumor quadrants. Karyotypic abnormalities were also found in 4 out of 9 macroscopically tumor-free samples from the surrounding tissue; in 2 of these samples, a ductal carcinoma in situ was detected histologically, and the cytogenetic evidence suggests that the remaining 2 samples also contained neoplastic cells. Quantitative analysis of the findings revealed a statistically significant higher frequency of karyotypically abnormal cells in samples with a histologic diagnosis of carcinoma vs. samples without any detected malignancy. That cells bearing cytogenetic evidence that they belong to the tumor parenchyma are left behind during breast-conserving surgery for carcinoma of the breast may account for the relatively high long-term local relapse rates seen in this disease.

DNA analysis of in situ ductal carcinoma of the breast via flow cytometry

Flow cytometric (FCM) DNA analysis of 41 clinical cases of ductal carcinoma in situ (DCIS) of the breast was performed on fine-needle aspirates of unfixed, frozen tissue. Based on analysis of a single tissue sample, abnormal DNA content was found in 35 (85%) of the cases, and 15 (37%) disclosed heterogeneity. If five or more samples were analyzed, then heterogeneity was found in eight of ten cases. No conclusive correlation could be found between DNA index (DI) and histopathology. Our results on DCIS demonstrate a very high concordance with invasive breast cancer with respect to the frequency of DNA nondiploid cases, distribution of DI, occurrence of multiple clones, and S-phase fraction. This indicates that major genetic alterations and DNA heterogeneity are early events in carcinogenesis that are already established at the preinvasive stage.

Chromosome abnormalities in bilateral breast carcinomas. Cytogenetic evaluation of the clonal origin of multiple primary tumors

BACKGROUND

Although acquired somatic mutations presumably are crucial in carcinogenesis, nothing is known about the chromosome aberrations of bilateral breast carcinomas.

METHODS

Eighteen specimens from 16 bilateral carcinomas were analyzed cytogenetically. The banding analysis was supplemented with fluorescence in situ hybridization with painting probes.

RESULTS

In two cases, the finding of the same clonal abnormalities in samples from both breasts indicated that the bilaterality had arisen through a metastatic process. In the remaining cases, the absence of similarities between the two sides indicated an independent origin of the two carcinomas. Also, in multifocal lesions within the same breast, examples were found both of karyotypically related and unrelated clones. Altogether, multiple clones without similarities were detected in nine specimens, sometimes together with other, karyotypically related clones. There was no indication that bilateral carcinomas of the breast are cytogenetically different from unilateral ones. The following chromosomal abnormalities were recurrent: der(1;16)(q10;p10), del(1)(q11-n12), del(1)(q42), and del(3)(p12-n13p14-n21).

CONCLUSIONS

Bilateral breast carcinomas have the same cytogenetic aberrations, including evidence of polyclonality, as unilateral carcinomas. The majority apparently arise independently, but some result from a metastasis from one breast to the other. In this sense, bilateral breast carcinomas are similar to multifocal breast cancer in general, of which bilateral tumors may represent a special case.