BAP1 is a novel regulator of HIF-1α

BAP1 is a powerful tumor suppressor gene characterized by haplo insufficiency. Individuals carrying germline BAP1 mutations often develop mesothelioma, an aggressive malignancy of the serosal layers covering the lungs, pericardium, and abdominal cavity. Intriguingly, mesotheliomas developing in carriers of germline BAP1 mutations are less aggressive, and these patients have significantly improved survival. We investigated the apparent paradox of a tumor suppressor gene that, when mutated, causes less aggressive mesotheliomas. We discovered that mesothelioma biopsies with biallelic BAP1 mutations showed loss of nuclear HIF-1α staining. We demonstrated that during hypoxia, BAP1 binds, deubiquitylates, and stabilizes HIF-1α, the master regulator of the hypoxia response and tumor cell invasion. Moreover, primary cells from individuals carrying germline BAP1 mutations and primary cells in which BAP1 was silenced using siRNA had reduced HIF-1α protein levels in hypoxia. Computational modeling and co-immunoprecipitation experiments revealed that mutations of BAP1 residues I675, F678, I679, and L691 -encompassing the C-terminal domain-nuclear localization signal- to A, abolished the interaction with HIF-1α. We found that BAP1 binds to the N-terminal region of HIF-1α, where HIF-1α binds DNA and dimerizes with HIF-1β forming the heterodimeric transactivating complex HIF. Our data identify BAP1 as a key positive regulator of HIF-1α in hypoxia. We propose that the significant reduction of HIF-1α activity in mesothelioma cells carrying biallelic BAP1 mutations, accompanied by the significant reduction of HIF-1α activity in hypoxic tissues containing germline BAP1 mutations, contributes to the reduced aggressiveness and improved survival of mesotheliomas developing in carriers of germline BAP1 mutations.

Catheter ablation of atrial fibrillation benefits the patients with heart failure and preserved ejection fraction as well as those with heart failure and reduced ejection fraction

Background

Although catheter ablation of atrial fibrillation (AF) has recently been shown to improve the cardiac function and even mortality in patients with heart failure (HF) and reduced ejection fraction (HFrEF), few studies have examined the outcomes of AF catheter ablation in patients with HF with preserved ejection fraction (HFpEF).

Purpose

To verify the impact of AF catheter ablation on the cardiac function and HF status in patients with HFpEF.

Methods

We studied 306 patients with HF who had a history of an HF hospitalization and/or preprocedural serum BNP levels >100pg/ml (age, 68.9±8.2 years old; male, 66.3%; non-paroxysmal AF, 63.1%, left atrial diameter [LAD], 42.5±6.3 mm; left ventricular ejection fraction [LVEF], 60.6±12.0%) out of 596 consecutive patients who underwent pulmonary vein isolation-based catheter ablation of AF. The patients with an LVEF ≥50% were defined as having HFpEF (n=262; age, 69.0±8.2 years old; male, 64.5%; non-paroxysmal AF, 61.8%, LAD, 42.1±5.9 mm; left LVEF, 64.0±8.2%) and the remaining patients with an LVEF <50% were defined as having HFrEF (n=44, age, 67.9±8.7 years old; male, 77.0%; non-paroxysmal AF, 70.5%, LAD, 44.9±8.2 mm; LVEF, 40.1±10.2%). The patients received periodic follow-ups for 12 months after the catheter ablation. The cardiac function parameters including the echocardiographic findings and HF functional status of the patients were compared between baseline and 12 months, stratified by the HF subgroup.

Results

AF recurred in 60 patients with HFpEF (22.9%) and in 14 with HFrEF (31.8%) during the 12 month follow-up (p=0.27), however, sinus rhythm was maintained at 12 months in most of the patients (253 patients with HFpEF [96.6%] and 42 patients with HFrEF [95.5%]) (p=0.71). Figure 1 compares the changes in the cardiac function parameters and NYHA functional class from baseline to the 12-month follow-up stratified by the HF subgroup. Both the patients with HFpEF and HFrEF had significant improvements in the serum BNP levels, chest thorax ratio, and LVEF determined by echocardiography. LA reverse remodeling as shown by a significant reduction in the LAD was observed in both HF subgroups, however, the E/E', an index of the LV diastolic function, did not significantly change in either of the subgroups. Similar to the patients with HFrEF, an improvement in the NYHA functional class was seen in those with HFpEF.

Conclusions

Catheter ablation of AF may benefit patients with HFpEF as well as those with HFrEF. Sinus rhythm maintenance achieved by AF catheter ablation in patients with HFpEF may lead to LA reverse remodeling and a better LV systolic function, thereby improving the NYHA functional class. It is unclear whether changes in the LV diastolic function may contribute to this favorable process.

Funding Acknowledgement

Type of funding source: None

Germline BAP1 mutations induce a Warburg effect

Carriers of heterozygous germline BAP1 mutations (BAP1^+/−) develop cancer. We studied plasma from 16 BAP1^+/− individuals from 2 families carrying different germline BAP1 mutations and 30 BAP1 wild-type (BAP1^WT) controls from these same families. Plasma samples were analyzed by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS), ultra-performance liquid chromatography triple quadrupole mass spectrometry (UPLC-TQ-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). We found a clear separation in the metabolic profile between BAP1^WT and BAP1^+/− individuals. We confirmed the specificity of the data in vitro using 12 cell cultures of primary fibroblasts we derived from skin punch biopsies from 12/46 of these same individuals, 6 BAP1^+/− carriers and 6 controls from both families. BAP1^+/− fibroblasts displayed increased aerobic glycolysis and lactate secretion, and reduced mitochondrial respiration and ATP production compared with BAP1^WT. siRNA-mediated downregulation of BAP1 in primary BAP1^WT fibroblasts and in primary human mesothelial cells, led to the same reduced mitochondrial respiration and increased aerobic glycolysis as we detected in primary fibroblasts from carriers of BAP1^+/− mutations. The plasma and cell culture results were highly reproducible and were specifically and only linked to BAP1 status and not to gender, age or family, or cell type, and required an intact BAP1 catalytic activity. Accordingly, we were able to build a metabolomic model capable of predicting BAP1 status with 100% accuracy using data from human plasma. Our data provide the first experimental evidence supporting the hypothesis that aerobic glycolysis, also known as the ‘Warburg effect’, does not necessarily occur as an adaptive process that is consequence of carcinogenesis, but rather that it may also predate malignancy by many years and facilitate carcinogenesis.

Expression of oestrogen receptor-? in apocrine carcinomas of the breast

AIMS

Apocrine carcinoma of the breast seldom expresses oestrogen receptors (ER) or progesterone receptors (PR), but frequently expresses androgen receptors (AR). Because of this unusual hormone receptor status, it has been suggested that oestrogens have a less important role in the pathogenesis of apocrine carcinoma. The ER status of apocrine carcinoma has been studied for one kind of ER, the classic receptor now named ER-alpha; however, the status of ER-beta, a secondary oestrogen receptor, has not been examined systematically in apocrine carcinoma. The aim was to study ER-beta status in apocrine carcinoma.

METHODS AND RESULTS

The expression of ER-beta was examined immunohistochemically in 48 apocrine carcinomas and compared with clinicopathological factors and ER-alpha, PR and AR status. ER-beta positivity was observed in 35 cases (73%), regardless of any clinicopathological factors or the status of other receptors. The results of ER-beta mRNA analysis supported the immunohistochemical results.

CONCLUSIONS

The significance of oestrogens in apocrine carcinoma should not be dismissed at present when the role of ER-beta remains to be determined. Studying the action of oestrogen or antioestrogen in apocrine carcinoma may reveal a role for ER-beta independent of ER-alpha and raise the potential of hormonal therapy for these tumours.

CIH-Tokyo Experience with Breast-Conserving Surgery without Radiotherapy: 6.5 Year Follow-Up Results of 1462 Patients

When breast-conserving therapy was introduced at the Cancer Institute Hospital (CIH) in Tokyo in 1986, we instituted our own strategy as follows: 1) every effort is to be made for complete tumor resection while avoiding deformity of the breast, and 2) radiotherapy (RT) is applied only to the patients with positive surgical margins. This is, in turn, to clarify the group of patients in whom postoperative RT can be safely spared. Among 9670 patients operated on for primary breast cancer during the 16.5 year period from 1986 to 2002 at CIH, there were 2449 patients who underwent breast-conserving surgery (BCS). During the 6.5 years mean follow-up period, ipsilateral intrabreast tumor recurrence (IBTR) developed in 99 of the 2449 patients, with an overall rate of 4.0% and an annual rate of 0.62%. These 2449 patients were categorized into four subgroups according to either negative or positive margins and with or without radiotherapy. The IBTR rates and the number of patients in each subgroup were 5.5% in 1351 margin(-)RT(-) patients, 1.0% in 307 margin(-)RT(+) patients, 2.4% in 680 margin(+)RT(+) patients, and 4.5% in 111 margin(+)RT(-) patients. These results either with or without RT seem to be quite comparable to or even better than the results of BCS with RT reported from Western countries, where less emphasis seems to be placed on completeness of the local tumor resection with BCS, while RT is administered to basically all patients following BCS. IBTR was categorized into true recurrence (TR) and second primary lesion (SP) according to the margin status at the time of BCS, the former being lesions developed in patients with positive margins and the latter being those in patients with negative margins. It was demonstrated that in patients with positive margins, TR was much more common than SP, whereas in patients with negative margins, these incidences were just the opposite (i.e., TR was 60% less common than SP) and postoperative RT was effective in preventing both TR and SP, the effect on the latter being much more striking. With RT, the incidence of developing TR in patients who had positive margins was reduced to almost equal to that in margin(-) patients treated with no RT. Our method of IBTR categorization is based on biological consideration and detailed histopathologic examination, and appears to be the only biologically reasonable means so far that has been proposed for distinction between these two biologically different entities. TR and SP can be further reduced to exceptionally low levels in patients who received RT despite negative margins, though it would not seem reasonable to administer RT to all of these patients because the actual number of patients who would benefit is comparatively small. From these observations, it seems that our imaging, pathologic examination, and surgical approaches for patients who are candidates for BCS have been highly valid, and our criteria for sparing postoperative RT as well as categorization of IBTR into TR and SP are quite appropriate. Although our results with BCS seem to deserve wide recognition, they are not from randomized clinical trials, so the findings must be confirmed by a study in order to investigate whether the results at CIH can be applied generally at other institutions.

Expression of GCDFP-15 and AR decreases in larger or node-positive apocrine carcinomas of the breast

AIMS

Apocrine carcinoma of the breast is typically, though not always, positive for gross cystic disease fluid protein-15 (GCDFP-15). In order to clarify the clinical significance of GCDFP-15 in apocrine carcinomas, GCDFP-15 expression was examined in apocrine carcinomas of different stages and compared with clinicopathological factors. Apocrine lesions reportedly exhibit an unusual immunohistochemical status, expressing androgen receptors (AR) instead of oestrogen receptors (ER), progesterone receptors (PR), or bcl-2. Their expression was also examined.

METHODS AND RESULTS

Fifty-two apocrine carcinomas were examined immunohistochemically. Thirty-nine (75%) and 29 (56%) were positive for GCDFP-15 and AR, respectively. GCDFP-15 positivity was significantly lower in infiltrating carcinomas than intraductal carcinomas (P = 0.0111). In infiltrating carcinomas, GCDFP-15 positivity was significantly low in tumours > or = 15 mm (P = 0.0005) and node-positive tumours (P = 0.0004). Similar phenomena were observed for AR. Rare cases were positive for ER (3.8%), PR (5.8%), and bcl-2 (1.9%).

CONCLUSIONS

GCDFP-15 positivity is transient and should not be considered a definitive marker of apocrine carcinomas. Cases which have apocrine features but lack GCDFP-15 expression should rather be considered as advanced apocrine carcinomas. ER/PR/bcl-2 negativity will sometimes be helpful to confirm the diagnosis of apocrine carcinoma, because it is more consistent than GCDFP-15/AR positivity.

Sentinel node detection using 99mTc-rhenium sulphide colloid in breast cancer patients: evaluation of 1 day and 2 day protocols, and a dose-finding study

Sentinel node (SN) biopsy is a promising replacement for standard axillary lymph node dissection for the staging of early breast cancer, and various techniques have been studied to identify SNs with dye or radioactive colloid. This study assesses the effect of the dose of radioactivity and the time before biopsy in order to set standards for the use of 99mTc-rhenium sulphide for the detection of SNs in breast cancer patients. Sixty patients with stage T1-2 N0 M0 breast cancer underwent SN biopsy, which was immediately followed by standard axillary dissection to confirm the SN results. For SN biopsy, 99mTc-rhenium colloid was injected peritumorally. A 1 day (morning injection and afternoon surgery) or 2 day (day before afternoon injection and morning surgery) protocol was applied. A dose-finding study was performed simultaneously using 7.4-37 MBq for the 1 day protocol and 37-74 MBq for the 2 day protocol. A scintigram was taken at 2 h for the 1 day protocol and 16 h for the 2 day protocol. After the injection of blue dye, SN biopsy was performed with a gamma probe, followed by standard axillary node dissection. The radiation exposure received by the surgical team during the operation was monitored. Histopathological comparison between SNs and axillary nodes was performed. Patient characteristics that might affect the radiocolloid uptake by SNs were assessed. SNs were identified in all patients regardless of the dose or administration protocol used. Two patients showed false negative pathological SN results, and the negative predictive value was 96% and the positive predictive value was 100%. In addition, radiation exposure to the surgical team and the amount of radioactive surgical waste were low, especially at lower doses. Two groups of patient characteristics were related to SN uptake. One was the body mass index (BMI) and the other was the age or menopausal status. Patients with a larger BMI tended to take up a smaller amount of 99mTc colloid. Older or post-menopausal patients showed lower SN uptake. 99mTc-rhenium sulphide colloid is an efficient radiopharmaceutical for SN detection. Both 1 day and 2 day protocols have equally good efficacy, and the recommended dose is 7.4 MBq for the 1 day protocol and 37 MBq for the 2 day protocol. Patients with larger BMI and older or post-menopausal patients tend to take up less 99mTc colloid.

Breast conserving treatment without radiotherapy

Radiotherapy (RT) is not always necessary for the prevention of ipsilateral breast recurrence in cases where cancer is not detected in the remaining breast tissue after breast conserving surgery. In addition, under these circumstances, the rate of a second primary cancer of the remaining breast is theoretically equal to the rate of contralateral breast cancer. In performing breast conserving treatment (BCT) at our institution we do not treat with RT if a strict serial pathological examination of the specimen (every 5 mm) reveals that the case has been safely resected (negative surgical margins). From 1986 to 1998, 827 patients (157 were ductal carcinoma in situ, and 670 were invasive) underwent BCT without RT at the Cancer Institute Hospital. Ipsilateral breast cancer was observed in 46 cases or 5.6% (0.85% annually) during a median observation period of 67 months. Of these 46 cases, 19 (2.3%) were diagnosed as a recurrence and 27 cases (3.3%) were second primary cancers. This recurrence rate is equivalent to the rate observed in 406 cases of BCT (1.7%) that were treated with RT. Most of these cases had shown positive surgical margins. Furthermore, the rate of occurrence of second cancers is not significantly different from the rate of occurrence of contralateral breast cancers. These results suggest that, by selecting irradiation cases based on careful pathological examinations, BCT can be safely performed.

Breast carcinoma in women over the age of 85: distinct histological pattern and androgen, oestrogen, and progesterone receptor status

AIMS

The pathogenesis of breast carcinoma in very elderly women is of interest, because oestrogen levels are likely to be extremely low during the development of the disease. In an effort to understand the pathogenesis of breast carcinoma in these women, this study was undertaken to compare the histological patterns and hormone receptor status of breast carcinomas arising in very elderly and younger women.

METHODS AND RESULTS

Thirty-seven breast carcinomas from women over the age of 85 years at the time of their operation were examined histologically and compared with those from a large group of premenopausal women. The proportions of mucinous carcinoma and apocrine carcinoma were significantly greater in older women. The expression of steroid hormone receptors was studied immunohistochemically. Androgen receptor-positive carcinomas were significantly more frequent among older women, whereas progesterone receptor-positive carcinomas were significantly less frequent. There was no statistically significant difference in oestrogen receptor-alpha or -beta expression between the tumours from both groups.

CONCLUSION

Breast carcinomas in women over the age of 85 years have a different morphological spectrum from carcinomas in younger age groups and may have different pathogenesis mechanisms that may be more dependent on androgen and androgen receptor interaction. Differences from the results of the other studies are discussed.

Evaluation of HER2 status: for the treatment of metastatic breast cancers by humanized anti-HER2 Monoclonal antibody (trastuzumab) (Pathological committee for optimal use of trastuzumab)

For the treatment of patients with metastatic breast cancer by humanized anti- human epidermal growth factor receptor type 2 (HER2) antibody (trastuzumab), it is important to evaluate HER2 status adequately. "A guideline for HER2 testing" and "HER2 atlas" produced by the "Pathological committee for optimal use of trastuzumab" are introduced in this report. Appropriate evaluations of biological markers are essential for targeting therapy.

Detection of HER-2/neu (c-erb B-2) DNA amplification in primary breast carcinoma. Interobserver reproducibility and correlation with immunohistochemical HER-2 overexpression

BACKGROUND

Fluorescent in situ hybridization (FISH) has been shown to be one of the most reliable methods with which to estimate the status of the HER-2/neu (or c-erb B-2) oncogene at the DNA level.

METHODS

To study interobserver reproducibility and to determine more clinically correlated criteria for HER-2/neu alterations, two observers independently estimated HER-2/neu DNA status. The correlation between the consensus HER-2/neu DNA status by FISH and HER-2/neu protein status detected by immunohistochemistry (IHC) using a polyclonal antibody was studied in 216 surgically resected breast carcinomas and 34 noncancerous tissues.

RESULTS

According to the HER-2/CEP17 ratio and mean HER-2 copies per nucleus, agreement level of HER-2/neu amplification was shown to be nearly perfect between two observers (kappa statistic (kappa) = 0.94 and kappa = 0.84). Finally, 40 tumors (19%) were judged to have HER-2/neu DNA amplification, with 6 having low-level amplification (> or = 2 but < 3 folds) and 34 having high-level amplification (> or = 3 folds). One hundred seventy-six other tumors, including 3 tumors that only 1 of the observers determined to be low-level amplifiers, and 34 noncancerous tissues had no detected amplification. The DNA amplification status was concordant between invasive and intraductal components in 14 carcinomas. HER-2/neu protein overexpression of moderate (2+) or high (3+) intensity based on IHC was detected in 51 carcinomas (24%), and was 2+ in 20 carcinomas and 3+ in 31 carcinomas. The HER-2/CEP17 ratio of > or = 2 was concordant with IHC findings of 2+/3+ in 91% of carcinomas (195 of 215 carcinomas), with a sensitivity of 70% (35 of 50 carcinomas) and a specificity of 97% (160 of 165 carcinomas). High-level amplification was detected in 29 of 31 IHC 3+ cases (94%), but in only 5 of 20 IHC 2+ cases (25%) and 0 in 165 IHC 0/1+ cases. All 34 cases with high-level amplification showed an IHC score of 3+ (29 cases) or an IHC score of 2+ (5 cases), but only 1 case was found to have an IHC score of 3+ and the remainder were IHC 0/1+ in 6 low-amplification cases. The concordance rate of the high-level amplification with an IHC score of 3+ was 97% (208 of 215 cases), with a sensitivity of 94% (29 of 31 cases) and a specificity of 97% (179 of 184 cases).

CONCLUSIONS

The results of the current study indicated that high-level HER-2/neu amplification and an IHC score of 3+ nearly optimally identified breast carcinomas with clinically and biologically significant HER-2/neu activation. Conversely, it was confirmed that careful interpretation of test results is required in the case of low-level amplification and/or an IHC score of 2+.

Detection of HER-2/neu (c-erb B-2) DNA amplification in primary breast carcinoma. Interobserver reproducibility and correlation with immunohistochemical HER-2 overexpression

BACKGROUND

Fluorescent in situ hybridization (FISH) has been shown to be one of the most reliable methods with which to estimate the status of the HER-2/neu (or c-erb B-2) oncogene at the DNA level.

METHODS

To study interobserver reproducibility and to determine more clinically correlated criteria for HER-2/neu alterations, two observers independently estimated HER-2/neu DNA status. The correlation between the consensus HER-2/neu DNA status by FISH and HER-2/neu protein status detected by immunohistochemistry (IHC) using a polyclonal antibody was studied in 216 surgically resected breast carcinomas and 34 noncancerous tissues.

RESULTS

According to the HER-2/CEP17 ratio and mean HER-2 copies per nucleus, agreement level of HER-2/neu amplification was shown to be nearly perfect between two observers (kappa statistic (kappa) = 0.94 and kappa = 0.84). Finally, 40 tumors (19%) were judged to have HER-2/neu DNA amplification, with 6 having low-level amplification (> or = 2 but < 3 folds) and 34 having high-level amplification (> or = 3 folds). One hundred seventy-six other tumors, including 3 tumors that only 1 of the observers determined to be low-level amplifiers, and 34 noncancerous tissues had no detected amplification. The DNA amplification status was concordant between invasive and intraductal components in 14 carcinomas. HER-2/neu protein overexpression of moderate (2+) or high (3+) intensity based on IHC was detected in 51 carcinomas (24%), and was 2+ in 20 carcinomas and 3+ in 31 carcinomas. The HER-2/CEP17 ratio of > or = 2 was concordant with IHC findings of 2+/3+ in 91% of carcinomas (195 of 215 carcinomas), with a sensitivity of 70% (35 of 50 carcinomas) and a specificity of 97% (160 of 165 carcinomas). High-level amplification was detected in 29 of 31 IHC 3+ cases (94%), but in only 5 of 20 IHC 2+ cases (25%) and 0 in 165 IHC 0/1+ cases. All 34 cases with high-level amplification showed an IHC score of 3+ (29 cases) or an IHC score of 2+ (5 cases), but only 1 case was found to have an IHC score of 3+ and the remainder were IHC 0/1+ in 6 low-amplification cases. The concordance rate of the high-level amplification with an IHC score of 3+ was 97% (208 of 215 cases), with a sensitivity of 94% (29 of 31 cases) and a specificity of 97% (179 of 184 cases).

CONCLUSIONS

The results of the current study indicated that high-level HER-2/neu amplification and an IHC score of 3+ nearly optimally identified breast carcinomas with clinically and biologically significant HER-2/neu activation. Conversely, it was confirmed that careful interpretation of test results is required in the case of low-level amplification and/or an IHC score of 2+.

Association of allelic losses at 3p25.1, 13q12, or 17p13.3 with poor prognosis in breast cancers with lymph node metastasis

To identify specific allelic losses that might correlate with postoperative mortality of patients with node-positive breast carcinomas, we examined tumors from a cohort of 263 such patients, who were followed clinically for 5 years postoperatively, for allelic losses among 18 microsatellite markers. Patients whose tumors had lost an allele at 3p25.1, 13q12, or 17p13.3 had significantly higher risks of mortality than those whose tumors retained both alleles at those loci. At 3p25.1, the 5-year mortality rate was 33.8% among patients with losses vs. 16.8% with retention (P = 0.0154); at 13q12, 30.3% vs. 13.0% (P = 0.0241); and at 17p13.3, 30.4% vs. 16.2% (P = 0.0243). Combined losses at 3p25.1 and 17p13.3 increased the predicted postoperative mortality risk by a factor of 4.9 (5-year mortality rate of 38.2% vs. 8.0%, P = 0.0006), and combined losses at 3p25.1 and 13q12 raised the predicted postoperative mortality risks by a factor of 2.9 (34.7% vs. 12.7%, P = 0.0441). These data indicate that loss of heterozygosity (LOH) at any one or a pair of loci at 3p25.1, 13q12, or 17p13.3 is a significant predictor of postoperative mortality for breast-cancer patients.

Overrepresentation of the EBAG9 gene at 8q23 associated with early-stage breast cancers

EBAG9, an estrogen-responsive gene located at 8q23 was identified in an effort to clone CpG-binding sites. Its product was later found to be identical to RCAS1, a cancer cell-surface antigen implicated in immune escape. We determined the sequence of the complete cDNA and the genomic structure for EBAG9. EBAG9 gene copy number in 21% (27 of 129) primary breast cancers we examined; EBAG9 mRNA was consistently expressed in cancer cell lines. Detailed physical mapping of the 8q arm, including polymorphic markers for EBAG9 and the CMYC loci, revealed allelic gain of either EBAG9, CMYC, or both, in 45% (58 of 129) of the breast cancers we examined. The EBAG9 gene was increased exclusively in 16 of the 27 tumors showing gain at that locus; the other 11 showed gain of a larger chromosomal region containing both EBAG9 and CMYC. Analysis of subsequent series of 144 primary breast cancers for allelic gain at EBAG9 and CMYC locus showed a similar degree of gain at EBAG9, CMYC, or both. When a total of 273 breast cancers from two series were combined and analyzed for clinicopathological correlation, almost all of the tumors with EBAG9 increased but not those with CMYC. Twenty-eight of 29 were T1/T2 stage carcinomas (<5 cm in diameter), whereas one third (21 of 61) of the tumors in which CMYC was increased but EBAG9 was not, were advanced T3-stage tumors (P = 0.0012). These data suggest that EBAG9 and CMYC gene are independent targets of gain and that overrepresentation of EBAG9 may play a specific role in early stages of breast carcinogenesis.

A case of leiomyoma of the breast

Leiomyomas are common in the genitourinary and gastrointestinal tracts and less frequent in skin and soft tissue. It is quite uncommon for them to develop in the breast, especially in the breast parenchyma. Only 12 cases of leiomyoma in the breast parenchyma proper apart from the areola have been reported. We present a thirteenth case, the first to be reported in Japan. Its clinical features, mammographic and ultrasonographic findings, histological and immunohistochemical characteristics are quite consistent with previous reports.

Fetal therapy with rhIGF-1 in a rabbit model of intrauterine growth retardation

BACKGROUND

Intrauterine growth retardation (IUGR) may, in part, be due to a deficiency of insulin-like growth factor-1 (IGF-1). The objectives of this study were to determine the relationship between fetal serum IGF-1 levels and fetal and placental size in a rabbit model of IUGR and to compare two techniques of selective, exogenous IGF-1 administration (transamniotic and branch uterine arterial catheter infusion) to growth-retarded fetuses in utero.

MATERIALS AND METHODS

Pregnant rabbits (n = 6) had their fetuses harvested near term (31 days) for fetal and placental weighing and serum collection. Growth-retarded fetuses were selectively infused for 7 days with recombinant human IGF-1 (rhIGF-1; 1,440 ng/day) either through a transamniotic catheter (n = 8) or via an adjacent uterine arterial branch catheter (n = 6). Opposite horn runts were sham catheterized, but not infused. At term, the fetal runt pairs and their placentas were harvested and weighed, and their serum was collected. The correlation between fetal and placental weight and endogenous serum IGF-1 was calculated (Pearson coefficient, r), while paired t-tests were used to compare the means between the IGF-1-infused and control groups.

RESULTS

There was a significant correlation between fetal (r = 0.4230; P = 0.022) and placental weight (r = 0.4166; P = 0.025) and endogenous serum levels of IGF-1. Transamniotic infusion of rhIGF-1 was associated with an increase in serum IGF-1 level (254 +/- 79 vs 351 +/- 101 ng/ml, P = 0.04) and placental weight (5.4 +/- 2.3 vs 7.1 +/- 3.2 g, P = 0.005), and with a trend toward increased fetal weight between matched fetal runt pairs. Fetal mortality in the uterine arterial catheterized group was 76%, and there was no significant difference in fetal or placental weight or IGF-1 levels between infused and noninfused survivors.

CONCLUSIONS

Endogenous fetal serum levels correlate with fetal and placental size in the rabbit IUGR model. Transamniotic administration of rhIGF-1 significantly increases serum IGF-1 levels and placental weight of fetal runts, while uterine vessel catheterization results in prohibitive fetal mortality and does not increase fetal or placental growth or IGF-1 levels.

Surgery for ductal carcinoma in situ

BACKGROUND

Ductal carcinomas in situ (DCIS) are sometimes treated too aggressively by surgery. We discuss minimal invasive surgery for DCIS on the basis of our experience at the Cancer Institute Hospital in Tokyo.

METHODS

We performed surgery for 667 cases of DCIS between 1987 to 1998. This twelve year period we divided into three periods; 1987-1990,1991-1994, and 1995-1998.

RESULTS

DCIS comprised 10% of all breast cancers, and tended to increase in incidence over time. The number of minimally invasive procedures such as breast conserving treatment (BCT), surgery without axillary dissection, and day surgery increased in later periods. In BCT for DCIS the surgical margin status is the most important factor, the rate of negative surgical margins was higher in DCIS than invasive cancer, and especially high in cases of mammographically detected nonpalpable cancer, the incidence of which is increasing yearly. The outcome of the 667 cases was very good. No distant metastases were observed, and the incidence of ipsilateral breast cancer(including second primary cancer) in these cases was 5%

CONCLUSIONS

Because small cancers, including nonpalpable cases, will be detected more frequently, minimal invasive surgery will become more common for DCIS.

Is the UICC pathological node status system useful? Comparison with the Japanese Breast Cancer Society pathological node status system

BACKGROUND AND OBJECTIVES

The UICC and the Japanese Breast Cancer Society have different TNM classifications. There is a large discrepancy between the pathological node status in the UICC (UICC-NS) and JBCS (JBCS-NS) systems. We compared the UICC-NS with the JBCS-NS.

METHODS

Reviewed were data on 1,684 invasive ductal carcinomas at the Cancer Institute Hospital from 1981 to 1986. Each case was categorized according to the UICC-NS and JBCS-NS, respectively. Overall survival 10 years after surgery (OS) by UICC-NS and JBCS-NS was calculated by the Kaplan-Meier method.

RESULTS

OS with UICC-NS and number of case were, respectively, 87.8% and 968 for pN0, 83.9% and 93 for pN1a, 71.6% and 190 for pN1bi, 60.0% and 25 for pN2, 58.8% and 51 for pN1bii, 55.7% and 238 for pN1biii, 54.2% and 24 for pN1biv, 44.8% and 58 for pN3, and 20.6% and 34 for pM (LYM). Differences between pN1a and pN1bi and pN3 and pM (LYM) were significant (p < 0.05). In JBCS-NS, they were 87.8% and 968 for n0, 75.3% and 384 for n1 alpha, 51.3% and 152 for n1 beta, 46.6% and 141 for n2, 21.2% and 33 for n3, 0% and 2 for n4d and n4i, respectively. Differences between n0 and n1 alpha, n1 alpha and n1 beta, and n2 and n3 were significant (p < 0.05).

CONCLUSIONS

With a large number of classification factors, UICC-NS was more complicated and hard to show significant difference in OS than JBCS-NS. But the latter also had redundant classifications. So, it is necessary to establish a new, simple, and easy-to-register node classification in future.

Allelic losses of loci at 3p25.1, 8p22, 13q12, 17p13.3, and 22q13 correlate with postoperative recurrence in breast cancer

We previously defined 18 chromosomal regions in which frequent allelic losses were observed in breast cancers (T. Sato et al., Cancer RES:, 50: 7184-7189, 1990; Y. Harada et al., Cancer (PHILA:), 74: 2281-2286, 1994; I. Ito et al., BR: J. Cancer, 71: 438-441, 1995; K. Tsukamoto et al., Cancer (PHILA:), 78: 1929-1934, 1996; S. Matsumoto et al., Genes Chromosomes Cancer, 20: 268-274, 1997; T. Yokota et al., JPN: J. Cancer RES:, 88: 959-964, 1997; K. Tsukamoto et al., Cancer (PHILA:), 82: 317-322, 1998; A. Iida et al., Genes Chromosomes Cancer, 21: 108-112, 1998; K. Fukino et al., Genes Chromosomes Cancer, 24: 345-350, 1999; T. Yokota et al., Cancer (PHILA:), 85: 447-452, 1999; Y. Utada et al., JPN: J. Cancer RES:, 91: 293-300, 2000). To identify specific allelic losses that might correlate with postoperative recurrence, we examined tumors from a cohort of 504 breast cancer patients, who were followed clinically for 5 years postoperatively, for allelic losses of 18 microsatellite markers. Patients whose tumors had lost an allele at 3p25.1, 8p22, 13q12, 17p13.3, or 22q13 had significantly higher risks of recurrence than those whose tumors retained both alleles at those loci; at 3p25.1, the 5-year recurrence rate was 27% among patients with losses versus 18% with retention (P = 0.0131); at 8p22, 27% versus 14% (P = 0.0129); at 13q12, 28% versus 15% (P = 0.0109); at 17p13.3, 27% versus 20% (P = 0.0482); and at 22q13, 29% versus 20% (P = 0.0477). These data indicate that loss of heterozygosity at any one of these five specific loci is a significant predictor of postoperative recurrence among patients who have undergone surgery for breast cancer. These allelic losses can serve as negative prognostic indicators to guide postoperative management of patients.

Allelic losses as prognostic markers for breast cancers

Specific allelic losses in the DNA of tumor cells are potential indicators of postoperative prognosis. Patients whose tumors showed allelic losses at 1p34, 3p25, 8p22, 13q12, 17p13.3, or 17q21.1 had a significantly higher risk of postoperative mortality than women whose tumors retained both alleles at those loci (the 5-year mortality rates in patients with loss vs those with retention were: at 1p34, 23% vs 10%, P = 0.0100; at 3p25, 22% vs 9%, P = 0.0014; at 8p22, 24% vs 7%, P = 0.0177; at 13q12, 19% vs 8%, P = 0.0093; at 17p13.3, 19% vs 9%, P = 0.0078; and at 17q21.1, 17% vs 10%, P = 0.0475). Allelic losses at these loci may serve as negative prognostic indicators to guide postoperative management, especially in the selection of patients who should be offered intensive adjuvant therapy.

[Radiation therapy for brain metastases from breast cancer by histological classification]

One hundred thirteen patients with metastatic brain tumor from breast cancer who were treated with external irradiation between 1989 and 1997 at Cancer Institute Hospital were studied. The patients were all histopathologically proven to have invasive ductal carcinoma (scirrhous type 54 cases, papillotubular type 18, solid-tubular type 41). The patients were evaluated for efficacy and histopathological subtypes. The time interval between the diagnosis of breast cancer and brain metastases was 53.6 months for the scirrhous type, 75.0 months for the papillotubular type, and 35.5 months for the solid-tubular type. The time interval between the diagnosis of initial distant metastases and brain metastases was 14.3 months for the scirrhous type, 22.5 months for the papillotubular type, and 12.5 months for the solid-tubular type. Efficacy rates (CR + PR) for external irradiation of the brain metastases were 40.0% for the scirrhous type, 66.7% for the papillotubular type, and 36.6% for the solid-tubular type. The papillotubular type had a favorable efficacy rate compared with the other two types. Median survival time (MST) from the start of treatment for brain metastases and one-year survival rate were 5 months and 11.1% for the scirrhous type, 7 months and 41.5% for the papillotubular type, and 4 months and 28.3% for the solid-tubular type, respectively. No statistically significant difference between survival rates was observed among the histopathological types. Univariate analysis showed performance status, number of metastatic tumors, and existence of extracranial metastases without bony metastasis to be significantly related to prognosis. Multivariate analysis showed only extracranial metastases without bony metastases to be related to prognosis.

UV disinfection for reuse applications in North America

In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications. Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation. Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies. The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion. During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD. California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years. To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations. Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application. As a rule, the resulting effluents have low turbidity and suspended solids. For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse. This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

Allelic loss at 1p34-36 predicts poor prognosis in node-negative breast cancer

Allelic losses of specific chromosomal regions in the DNA of tumor cells, which imply loss of tumor suppressor genes normally resident at those loci, may become useful postoperative prognostic indicators for breast cancers that have not yet metastasized to lymph nodes. To examine whether specific allelic losses might correlate with postoperative disease-free survival, we tested tumors from a cohort of 228 node-negative breast cancer patients for allelic losses at 18 microsatellite loci chosen to represent either a known tumor suppressor gene or a region where genetic alterations are frequent in breast tumors. We followed the patients clinically for 5 years or until death (if patient death occurred before completion of 5 years of follow-up). Patients whose tumors had lost an allele at 1p34-36 bore significantly higher risks of postoperative recurrence than those whose tumors retained both alleles of the markers in that region [the 5-year recurrence rate was 15% among patients with losses versus 2% among patients with retention (P = 0.001)]. Multivariate analysis demonstrated that allelic loss at 1p34-36 was an independent postoperative predictor of shorter disease-free survival (hazard ratio, 5.8; P = 0.0117). Thus, allelic losses at 1p34-36 in a tumor might have a potential to serve as a negative prognostic indicator to guide postoperative management of breast cancer patients, especially in the selection of high-risk women who will benefit from adjuvant chemotherapy and endocrine therapy.

Identification of Rad51 alteration in patients with bilateral breast cancer

The human Rad51 gene, HsRAD51, is a homolog of RecA of Escherichia coli and functions in recombination and DNA repair. BRCA1 and BRCA2 proteins form a complex with Rad51, and these genes are thought to participate in a common DNA damage response pathway associated with the activation of homologous recombination and double-strand break repair. Additionally, we have shown that the pattern of northern blot analysis of the RadS gene is closely similar to those of the BRCA1 and BRCA2 genes. It is therefore possible that alterations of the Rad51 gene may be involved in the development of hereditary breast cancer. To investigate this possibility, we screened Japanese patients with hereditary breast cancer for Rad51 mutations and found a single alteration in exon 6. This was determined to be present in the germline in two patients with bilateral breast cancer, one with synchronous bilateral breast cancer and the other with synchronous bilateral multiple breast cancer. In both patients, blood DNAs showed a G-to-A transition in the second nucleotide of codon 150, which results in the substitution of glutamine for arginine. As this alteration was not present in any patients with breast or colon cancer examined, we assume that this missense alteration is likely to be a disease-causing mutation.

Loss of heterozygosity at 3p24-p25 as a prognostic factor in breast cancer

Differences in clinical course and biological characteristics among breast cancers will probably be explained ultimately by variations in the pattern of genetic alterations among the many genes that can play roles in carcinogenesis. Loss of heterozygosity (LOH) of a particular chromosomal region in a tumor, which presumably indicates loss of a growth-regulating 'tumor-suppressor' gene in that region, may represent a useful marker for postoperative prognosis. In earlier work we observed LOH at chromosomal regions 3p14-p21 and/or 3p24-p25 in a large proportion of breast cancers. To examine whether allelic losses in either of those regions might correlate with postoperative survival, we tested tumors from a cohort of 504 breast cancer patients for allelic losses of microsatellite markers in the relevant portions of chromosome 3p. Five years postoperatively, patients whose tumors had undergone LOH at 3p24-p25 were found to have borne significantly higher risks of mortality than women whose tumors retained both alleles at that locus; i.e. the 5-year mortality rate was 22% among patients with losses at 3p24-p25 vs. 9% with retentions of heterozygosity at that locus (P=0.0014). These data indicate that LOH at 3p24-p25 is a significant predictive factor for postoperative survival of patients who have undergone surgery for breast cancer.

Evaluation of the interobserver agreement in the number of mitotic figures of breast carcinoma as simulation of quality monitoring in the Japan National Surgical Adjuvant Study of Breast Cancer (NSAS-BC) protocol

In the National Surgical Adjuvant Study for Breast Cancer (NSAS-BC), node-negative breast cancers were divided into higher- and lower-risk groups according to the histopathological nuclear grade given at individual collaborating hospitals, and the higher-risk group was entered into a randomized protocol of adjuvant therapy. Because the nuclear grade was the composite of nuclear atypia and mitotic counts, maintenance of interobserver agreement in mitotic counts was indispensable for the success of the protocol study. Fourteen pathologists participating in the protocol judged whether or not 20 photomicrographs suspected of showing mitotic cancer-cell figures truly showed mitoses. After standardizing the counting method, these pathologists counted the number of mitotic figures per 10 high-power fields of hematoxylin-eosin-stained main-tissue sections of 20 tumors. Areas where mitotic counts were considered to be the most frequent by each pathologist were compared for these tumors. For the judgment of whether the photomicrograph indicated mitosis, the level of interobserver agreement was moderate (kappa = 0.569). In the observations of 20 tumors, interobserver agreement level of mitotic counts was moderate (kappa = 0.506), that of nuclear atypia scoring was fair (kappa = 0.265), and that of nuclear grading was substantial (kappa = 0.633). The counted area was almost the same among the observers in 9 tumors, split into two areas in 6, and dispersed in 5. Concordance in judgment was achieved in 7 of the first 9 and in all of the third 5, but only in one of the second 6. The cause of discordance was mostly derived from tumor heterogeneity and the difference in the site where mitoses were counted. Interobserver agreement level was considered to be satisfactory, and it was expected that the case entry would be performed appropriately in the protocol study. The selection of the counting area was confirmed to be important for the acquisition of high-level agreement level in mitotic counts.

Allelic loss at the 8p22 region as a prognostic factor in large and estrogen receptor negative breast carcinomas

BACKGROUND

Allelic losses of tumor suppressor genes, or the chromosomal regions harboring them, in the DNA of tumor cells may become useful postoperative prognostic indicators. The authors studied frequent loss of heterozygosity (LOH) on chromosome 8p22 and its association with disease progression that occurred later in patients with breast carcinoma.

METHODS

To examine whether allelic losses at 8p22 might correlate with postoperative survival during a 5-year period of prospective follow-up, the authors tested tumors from a cohort of 298 breast carcinoma patients informative for 8p22 markers. The tumors were tested for allelic losses of microsatellite markers D8S136 and D8S1106 located at 8p22, a chromosomal region where genetic alterations are frequent in breast carcinomas.

RESULTS

Among the 298 breast carcinoma patients, 154 (52%) lost alleles in tumors. Patients whose tumors had lost an allele at 8p22 had a significantly higher risk of postoperative mortality than those whose tumors retained both alleles at those loci; their 5-year mortality rates were 18% (26 patients died among 154 with losses at 8p22) versus 7% (10 patients died among 144 with retentions at 8p22) (P = 0.017). The 8p22 LOH was a significant independent prognostic factor for postoperative survival in a group of patients with large tumors (>2.1 cm) and in a group of patients with estrogen receptor negative tumors in both univariate and multivariate analyses. These data show that 8p22 LOH was a significant prognostic factor for the postoperative survival of certain clinical groups of patients who underwent surgery for breast carcinoma.

CONCLUSIONS

Allelic loss on chromosome 8p22 can serve as a negative prognostic indicator to guide the postoperative management of patients, especially patients with large tumors (>2.1 cm) and those with estrogen receptor negative tumors.

Mapping of target regions of allelic loss in primary breast cancers to 1-cM intervals on genomic contigs at 6q21 and 6q25.3

Allelic losses on the long arm of human chromosome 6 are frequently observed in cancers of the ovary, prostate, and breast. To identify the locations of putative tumor suppressor genes on 6q, we examined 192 primary breast cancers for patterns of allelic loss at 16 polymorphic microsatellite loci distributed along this chromosome arm. Allelic losses at one or more loci were observed in 105 (55%) of the tumors examined. Detailed deletion mapping with appropriate yeast artificial chromosome (YAC) contigs identified two distinct commonly deleted regions; one was confined to a 1-cM interval at 6q21 flanked by D6S1040 and D6S262 and the other to a 1-cM interval at 6q25.3 flanked by D6S305 and D6S411. Allelic losses at 6q21 were more frequent in invasive solid tubular and scirrhous carcinomas than in tumors of less aggressive histologic types (P = 0.0006). Allelic loss at 6q25.3 was associated with loss of progesterone receptor (P = 0.0256). Our results suggest the presence of two tumor suppressor genes for breast cancer on 6q that are likely to be associated with tumor progression and / or loss of hormonal dependency.

A quantitative model using mean and standard deviation for evaluation of interobserver agreement in nuclear atypia scoring of breast carcinomas in a protocol study

A quantitative model was devised for the purpose of evaluating interobserver agreement in the judgment of the nuclear atypia score of cancer cells in protocol studies. In this model, the mean nuclear atypia score (mu) among observers was considered to approximate the 'true' nuclear atypia score of the tumor, and with an identical mu the strength of interobserver agreement was evaluated by the difference between the ideal standard deviation (sigma) and the observed sigma in the slide conference session. This model was applied to the data of a total of 216 invasive ductal carcinomas acquired at eight slide conference sessions held for the standardization of nuclear atypia scoring and monitoring of interobserver agreement level for enrolled cases in a surgical adjuvant protocol on breast cancer. Compared with conventional percentage interobserver agreement and kappa statistics, the present model, named the lambda model, was more sensitive in detecting the improvement of interobserver agreement in nuclear atypia scoring with repetition of slide conference sessions. The lambda model was particularly effective for evaluating the session which included many intermediate cases with a score between 1 and 2 or between 2 and 3. Percentage interobserver agreement and kappa statistics could estimate the agreement irrespective of the number of observers, but the agreement tended to be underestimated when these intermediate cases were in the majority. The present method was considered to be complementary to conventional methods for evaluating interobserver agreement of cancer histology in protocol studies.

Fat intake and breast cancer risk in an area where fat intake is low: a case-control study in Indonesia

BACKGROUND

Associations of fat and other macronutrients with breast cancer risk are not clear in areas where fat intake is low.

METHODS

We conducted a hospital-based case-control study from 1992 to 1995 in Jakarta, Indonesia.

RESULTS

The study, based on 226 cases and 452 age and socioeconomic status matched controls, provided the following findings. (a) In the pre-marriage period, the greater the fat or protein consumption, the larger the risk, whereas decreasing risk with increasing carbohydrate intake was detected. The odds ratio (OR) for the highest quartile of intake relative to the lowest was 8.47 (95% CI: 4.03-17.8) for fat, 2.19 (95% CI: 1.30-3.69) for protein, and 0.16 (95% CI: 0.08-0.31) for carbohydrate. A positive association with fat and a negative one with carbohydrate were also observed for the post-marriage period, but of weaker magnitude compared to the pre-marriage period. (b) The effects of macronutrient intakes were stronger among premenopausal than among postmenopausal women. (c) Most of the associations of protein and carbohydrate were insignificant after adjustment for fat intake.

CONCLUSIONS

These findings suggest that fat intake might be an important determinant of breast cancer among populations with a low fat diet in Indonesia.

Mammographic and clinicopathological features of mucinous carcinoma of the breast

BACKGROUND

We attempted to improve the effectiveness of diagnostic techniques in mammographic imaging of mucinous carcinoma of the breast by defining the characteristics of mammographic images and investigating correlations between these images and various clinicopathological findings.

METHODS

Clinicopathological investigations of 92 lesions in 90 cases of mucinous carcinoma of the breast were made. Mammography demonstrated 80 lesions with identical tumor shadow characteristics and these were divided into three patterns, circumscribed, indistinct and blended. Correlations between clinicopathological findings and mammographic images were investigated.

RESULTS

Patients with mucinous carcinoma of the breast usually present with a palpable mass. The lymph node metastasis rate in this study was low and prognosis in the early postoperative period was satisfactory. On mammograms, the circumscribed pattern was the most frequent. The investigation of the correlation between histological sub-type and mammographic pattern showed a high percentage of pure type lesions exhibited in the circumscribed pattern while those of mixed histologic type often showed the indistinct pattern. Calcification frequency demonstrated on mammography was 75% for the indistinct and mixed patterns, and approximately 50% for the circumscribed pattern. A high rate of calcification seen outside the tumor shadow suggested a high frequency of invasion and the spread of cancer to neighboring tissues. The circumscribed pattern was least frequently associated with lymph node metastasis, followed by the indistinct and blended patterns in that order.

CONCLUSION

Investigation of clinicopathological factors and mammographic findings in mucinous carcinoma of the breast suggests that mammography provides clinically valuable information for the treatment of this disease. These findings indicate the importance of careful mammographic observation at the time of diagnosis.

Allelic loss at 1p34, 13q12, 17p13.3, and 17q21.1 correlates with poor postoperative prognosis in breast cancer

Allelic losses of tumor suppressor genes (TSGs), or the chromosomal regions harboring them, in tumor DNA may become useful postoperative prognostic indicators. To examine whether specific allelic losses might correlate with postoperative survival in a 5-year prospective follow-up, we tested tumors from a cohort of 264 breast cancer patients for allelic losses of 18 microsatellite markers representing either a known TSG or a region where genetic alterations are frequent in breast tumors. Patients whose tumors had lost an allele at 1p34, 13q12, 17p13.3, or 17q21.1 had significantly higher risks of postoperative mortality than those whose tumors retained both alleles at those loci (at 1p34, a 5-year mortality rate of 29% among patients with losses vs. 7% with retentions, P = 0. 0008; at 13q12, 31% vs. 10%, P = 0.0062; at 17p13.3, 24% vs. 13%, P = 0.026; and at 17q21.1, 31% vs. 13%, P = 0.0047). Furthermore, combined losses at 13q12 and 17p13.3 increased the predicted postoperative mortality risks by a factor of 9.6 (5-year mortality rate of 42% vs. 5% with retentions, P = 0.0001), and combined losses at 1p34 and 17p13.3 raised the predicted postoperative mortality risks by a factor of 8.6 (27% vs. 3%, P = 0.0064). We conclude that allelic losses at these loci can serve as negative prognostic indicators to guide postoperative management of patients. Genes Chromosomes Cancer 26:134-141, 1999.

Somatic mutation of the PTEN/MMAC1 gene in breast cancers with microsatellite instability

The extent to which microsatellite instability (MI) contributes to the etiology of breast cancer has not been established in any large-scale studies. We examined 528 samples of tumor DNA from patients with primary breast cancer for MI, using 14 polymorphic CA-repeat markers. The frequency of MI in these tumors was unexpectedly low (10/528, 1.9%). The ten MI+ tumors were analyzed for mutations in five potential target genes that contain simple repeat sequences (TGFBIIR, IGF2R, hMSH6, BAX and PTEN/MMAC1). A somatic insertion of an extra adenine in the (A)6 region at codon 321-323 (exon 8) of the PTEN/MMAC1 gene, leading to a frame-shift, was identified in one tumor. This observation represented the first documented instance of PTEN/MMAC1 alteration in a MI+ primary breast cancer.

Monitoring of interobserver agreement in nuclear atypia scoring of node-negative breast carcinomas judged at individual collaborating hospitals in the National Surgical Adjuvant Study of Breast Cancer (NSAS-BC) protocol

BACKGROUND

In the NSAS-BC protocol, the nuclear atypia and mitotic counts are to be judged by pathologists at each participating hospital for assessing high-risk node-negative breast cancers. Therefore, maintenance of interobserver agreement in diagnosis at a higher level is mandatory during the period of patient entry.

METHODS

Individual collaborating pathologists originally evaluated the histological eligibility of 107 cases. Three panel pathologists determined consensus diagnoses and 29-37 collaborating pathologists determined modal diagnoses of these cases at three slide conference sessions. The original diagnoses were compared with the consensus and modal diagnoses to estimate the percentage of erroneous judgments.

RESULTS

The agreement rate in histological type and nuclear atypia score was 69% (74/107) between the original and consensus diagnoses, 76% (81/107) between the original and modal diagnoses and 86% (92/107) between the consensus and modal diagnoses. The strength of interobserver agreement at the slide conference sessions was moderate (0.447-0.535) by kappa statistics. The original, consensus and modal diagnoses were concordant in 71 cases (66%), but were discordant in 36. Of 35 invasive ductal carcinomas with discordant diagnoses, the discordance arose from the intermediate tumor nature in 15, multiple factors in 13 and erroneous diagnosis in seven (6.5%), if the characteristics of the tumor were judged from the percentage interobserver agreement per tumor at the slide conferences.

CONCLUSION

Nuclear atypia scoring given at individual hospitals on case entry was almost reproducible among the pathologists. Continuous efforts are needed to improve interobserver agreement and to decrease erroneous diagnosis for protocol eligibility.

Frequent multiplication of chromosome 1q in non-invasive and papillotubular carcinoma of the breast

Carcinogenesis is considered to be a multistep process that may involve cumulative genetic alterations; one of these mechanisms, gain of chromosomal material, has the potential to activate tumor-promoting genes in breast carcinogenesis. Using 12 polymorphic microsatellite markers on the long arm of chromosome 1 (1q), we examined 130 sporadic breast carcinomas for abnormalities in the copy numbers of these loci in tumor cells using a differential PCR method. We also sought correlations between alterations on 1q and several clinicopathological parameters. At every locus examined, a 2-3-fold increase in copy number of an allele in tumor material was observed in one third of the tumors (46 of 130, 35%), indicating 'multiplication' of 1q. This multiplication involved the entire long arm in majority of those tumors (43 cases, 93%). The multiplication of 1q was observed more frequently in non-invasive ductal and papillotubular histological types than in solid-tubular and scirrhous types (13/25, 52% vs. 27/90, 30%) (P = 0.041). The predominant chromosomal alterations on 1q in breast carcinomas are found to be multiplications rather than losses. The multiplication represents polysomy of the entire region of 1q, and may confer a growth advantage during development and/or progression of non-invasive ductal and papillotubular histologic types of breast carcinomas.

Mapping of a new target region of allelic loss to a 6-cM interval at 21q21 in primary breast cancers

A detailed analysis of loss of heterozygosity (LOH) in breast cancers was performed with 11 microsatellite markers on the long arm of chromosome 21. Among the 142 tumors examined, 44 (31%) showed LOH at one or more loci. Peak LOH frequency was observed on band 21q21. Deletion mapping identified a new commonly deleted region in a 6-cM interval of 21q21 between loci D21S1432 and D21S1437, and raised the possibility that one or more tumor suppressor genes associated with breast cancer may exist in this region. Comparison of these alterations with clinicopathological parameters revealed an association of LOH on 21q with loss of progesterone receptor (P = 0.0013).

Frequent multiplication of chromosomal region 8q24.1 associated with aggressive histologic types of breast cancers

Carcinogenesis is considered to be a multi-step process that may involve cumulative genetic alterations. One such alteration, gain of chromosomal material, has the potential for activating genes that promote carcinogenesis in breast tissues. Using 14 polymorphic microsatellite markers on the long arm of chromosome 8 (8q), we examined 142 sporadic breast cancers for abnormalities in the copy-numbers of these loci. At each locus examined, a 2- to 3-fold increase in intensities of bands representing single alleles was observed in 57 (40%) of the tumors, indicating that 'multiplication' of the DNA sequence had occurred on 8q. A 16-cM region on 8q24.1 was commonly multiplied among the tumors with partial multiplications. Multiplication on 8q24.1 was observed more frequently in invasive solid-tubular or scirrhous tumors (48/92, 52%) than in less aggressive histologic types (7/25, 28%, P = 0.031). Thus, multiplication of tumor-promoting gene(s) located on 8q24.1 may play a role in the development and/or progression of a substantial proportion of primary breast cancers, particularly those of the invasive histology.

Frequent allelic loss at the TOC locus on 17q25.1 in primary breast cancers

Sporadic breast cancers often show allelic losses on the long arm of chromosome 17. Since the BRCA1 gene lies at 17q21.1 and the TOC locus, associated with esophageal cancer, lies at 17q25.1, either gene could be the target of those losses. We examined both loci in 178 primary breast cancers, using microsatellite markers covering the relevant regions of 17q, and observed allelic losses in 97 tumors (55%). Losses were most frequent at markers around the TOC locus (48% at D7S1839 and 43% at D17S1603), where we identified a distinct commonly deleted region within a I -cM interval. Another larger, separate commonly deleted region including the BRCA1 gene was also identified, which exhibited 45% of allelic loss (at D17S934). Allelic loss on 17q was more frequent in tumors of the solid-tubular histologic type (P = 0.0129) and in estrogen-negative and progesterone-negative tumors (P = 0.0281 and 0.0196, respectively). The results indicated that BRCA1 and TOC are independent targets of allelic loss on 17q in primary breast cancers, and that inactivation of the TOC locus in particular may play an important role in the genesis of sporadic breast tumors.

The location of positive nodes partly influences the prognostic value of the number of positive nodes in breast cancer patients

BACKGROUND

The aim was to determine whether the number of positive lymph nodes or the location of lymph node metastasis (location number) would permit a more accurate prediction of prognoses.

METHODS

We compared the survival rates of 3922 patients with primary breast cancer in relation to the location number and the number of positive lymph nodes. Survival rates were calculated by the Kaplan-Meier method and analyzed using the log rank test.

RESULTS

Within the n1 alpha group, the presence of one or two positive nodes was associated with significantly better survival than the presence of three positive nodes. These groups should therefore be distinguished. Within the n1 beta group, there was no significant difference in survival between patients with four and those with seven or more positive nodes. Comparisons of n1 beta and n2 patients after subgrouping by the number of positive nodes (4-9 and 10 or more) revealed a significantly poorer prognosis in the n2 group.

CONCLUSIONS

When the prognosis of breast cancer is considered from the viewpoint of lymph node metastasis, the location number as described in the General Rules is an excellent classification. However, we should be aware of possible differences in the prognosis depending on the number of positive nodes, as this is masked by the location number.

The efficacy and limitations of repeated slide conferences for improving interobserver agreement when judging nuclear atypia of breast cancer. The Japan National Surgical Adjuvant Study of Breast Cancer (NSAS-BC) Pathology Section

BACKGROUND

The pathology section of the Japan National Surgical Adjuvant Study of Breast Cancer protocol study was set up to establish histological criteria for assessing high-risk node-negative breast cancers and standardize the subjective criteria used by collaborating pathologists for nuclear grading of cancers.

METHODS

In order to standardize the nuclear atypia criteria, five slide conferences were held. A total of 57 observers assigned nuclear atypia scores to 119 breast carcinomas that were presented using a slide projector or a TV monitor and discussed their histological findings. The percentage interobserver agreements per tumor and per conference and kappa value per conference were estimated and compared among the conferences. The percentage intraobserver reproducibility per tumor between the last two conferences was compared with the percentage interobserver agreement for 20 tumors. The kappa value was also calculated for each of 27 observers to evaluate scoring reproducibility.

RESULTS

The percentage interobserver agreement per conference was constant (75-78%) throughout the five meetings and the rate of tumors with > 80% agreement per tumor became higher in later conferences. The kappa value was 0.42, 0.25, 0.42, 0.51 and 0.50 for the first, second, third, fourth and fifth conferences, respectively. The tumors with a lower percentage interobserver agreement also had a lower percentage intraobserver reproducibility and such scoring variations were attributed to the intermediate nature of the degree of tumor atypia. In 26 of 27 observers, intraobserver agreement for 20 tumors was estimated from the kappa value to range from moderate to almost perfect.

CONCLUSION

We concluded that the repeated slide conferences conducted by the pathology section were an effective means of standardizing the subjective histopathological criteria used to assess tumors. However, the achievement of a good scoring agreement would be difficult for tumors with an intermediate degree of atypia.

Localization of a tumor suppressor gene associated with the progression of human breast carcinoma within a 1-cM interval of 8p22-p23.1

BACKGROUND

Frequent allelic losses on the short arm of chromosome 8 in several types of human cancers, and deletion maps of this region in tumor DNAs, have suggested that 8p harbors one or more genes that are important for suppressing tumorigenesis in the tissues in question.

METHODS

To define the locations of potential tumor suppressor genes involved in breast carcinoma, the authors examined 144 primary breast carcinomas for loss of heterozygosity at 18 highly polymorphic microsatellite loci on 8p. They also sought correlations between allelic loss on 8p and several clinicopathologic parameters.

RESULTS

Allelic loss was observed in 74 of the 144 sporadic breast carcinomas examined. Whereas more than half of the informative tumors showed loss of an allele at every locus on the short arm, 32 showed partial or interstitial deletions. Deletion mapping in this panel of tumors identified two distinct commonly deleted regions, one in a 1-cM interval flanked by D8S511 and D8S1991 at 8p22-p23.1, and the other in a 16-cM interval flanked by D8S136 and D8S1477 at 8p22-p21. Allelic losses in both of these regions were observed more frequently in tumors of the solid-tubular or scirrhous type than in less aggressive histologic types. Furthermore, allelic loss in either region occurred more frequently in larger and infiltrative tumors (T1 < T2 < T3).

CONCLUSIONS

The association of allelic losses on 8p with advanced tumor stage and aggressive histologic type implies that loss or inactivation of one of at least two putative tumor suppressor genes on 8p may contribute to the progression of breast carcinoma.