Benjamin L. Schlechter

Quantitative DNA Fingerprinting May Distinguish New Primary Breast Cancer From Disease Recurrence

PURPOSE Approximately 10% of women with breast cancer develop a second breast tumor, either a new primary or a recurrence. Differentiating between these entities using standard clinical and pathologic criteria remains challenging. Ambiguous cases arise, and misclassifications may occur. We investigated whether quantitative DNA fingerprinting, based on allele imbalance (AI) or loss of heterozygosity (LOH), could evaluate clonality and distinguish second primary breast cancer from recurrence. METHODS We developed a scoring system based on the AI/LOH fingerprints of 20 independent breast tumors and generated a decision rule to classify any breast tumor pair as related or unrelated. We validated this approach on eight related tumors (cancers and synchronous positive lymph nodes). Finally, we analyzed paired tumors from 13 women (bilateral cancers, primary tumors and contralateral positive axillary lymph nodes, or two ipsilateral tumors). Each pairs genetic classification was compared with their clinical diagnosis and outcome. RESULTS Each independent cancer had a unique fingerprint. Every tumor pairs relationship was quantifiable. Six of eight related tumor pairs were genetically classified correctly, two were indeterminate, and none were misclassified. Among the 13 women with two cancers, four of five clinically indeterminate pairs could be classified genetically. In three of 13 women, the pairs classification contradicted the clinical diagnosis. These women had bilateral cancers genetically classified as related and disease progression. This challenges the paradigm that bilateral cancers represent independent tumors. Overall, women with tumors genetically classified as related had poorer outcomes. CONCLUSION Quantitative AI/LOH fingerprinting is a potentially valuable tool to improve diagnosis and optimize treatment for the growing number of second breast malignancies.

Tract formation following percutaneous endoscopic gastrostomy in an animal model

SummaryComplications of percutaneous endoscopic gastrostomy (PEG) have often been related to the application of excessive traction to the gastrostomy tube in an attempt to achieve immediate juxtaposition of the gastric and abdominal walls. Recent clinical reviews have suggested that complication rates can be reduced by avoiding such traction and leaving a longer tract between these structures. Laboratory evaluation of tract development has been lacking. The present study was designed to evaluate tract formation in an animal model. Eight mongrel dogs underwent PEG placement using silastic (n = 4) or latex (n = 4) catheters. Two animals from each group were subsequently sacrificed at 1 week and the remaining animals, at 2 weeks. In each animal, 6 cm catheter length was left between the gastric and the abdominal walls. This distance was assured by crossbar and suture fixation of the catheter at the skin entry site. Complete tract formation was evident in all animals at the time they were sacrificed, with no significant gross or histologie differences being noted between the silastic and the latex groups. Increased collagen deposition was noted at 2 weeks in comparison with that observed at 1 week. In an additional three animals, the same procedure was performed, but the catheter was not secured to the abdominal wall at the site of skin penetration. In these animals, tract formation was incomplete as late as at 2 weeks, but there were no associated complications. We conclude that early PEG tract formation is not dependent on the immediate proximity of the gastric and abdominal walls. The type of catheter used does not dictate the time course of early tract development. Failure to fix the catheter externally at the skin entry site results in retarded tract formation, although this does not appear to increase the incidence of catheter-related complications. Although the present study documents the safety and reliability of long tract formation, short tracts remain advantageous from the standpoint of catheter replacement and are associated with low complication rates when excessive traction is assiduously avoided.

A comparison of different suture techniques for microvascular anastomosis

Of the various techniques known, simple interrupted sutures remain the gold standard in the microanastomosis of vessels. Tying many knots, however, is time consuming. This may be of more significance with tissues such as the jejunum, which is significantly effected by ischemia time, or when several vessels are to be anastomosed. In this study, 60 femoral arteries of rabbits were divided into three equal groups. The arteries were then divided and repaired using simple interrupted, simple continuous, and continuous locked sutures. Application of the Bonferroni t-test revealed that both groups of arteries repaired using continuous sutures exhibited a statistically significant (p < 0.02) reduction in anastomosis time (50%) compared with interrupted suture techniques. However, there also was a 45% incidence of reduction in flow (9 of 21 anastomoses) when the simple running suture technique was utilized, giving the running locked suture unquestionable superiority.Schlechter B, Guyuron B. A comparison of different suture techniques for microvascular anastomosis. Ann Plast Surg 1994; 33:28–31

Allele Imbalance, or Loss of Heterozygosity, in Normal Breast Epithelium of Sporadic Breast Cancer Cases and BRCA1 Gene Mutation Carriers Is Increased Compared With Reduction Mammoplasty Tissues

PURPOSE Normal-appearing breast epithelium can contain genetic abnormalities, including allele imbalance (AI), also referred to as loss of heterozygosity. Whether abnormalities are associated with cancer or cancer risk is unknown. PATIENTS AND METHODS We performed a miniallelotype, using 20 microsatellites, on each of 460 histologically normal, microdissected breast terminal ducto-lobular units (TDLUs) from three groups of women: sporadic breast cancer patients (SP; n = 18), BRCA1 gene mutation carriers (BRCA1; n = 16), and controls undergoing reduction mammoplasty (RM; n = 18). We analyzed the results using Fishers exact tests, logistic regression, and generalized estimating equations. RESULTS AI was increased three-fold in SP and BRCA1 groups compared with RM. Both the number of TDLUs with AI increased (eight [5%] of 162 in the RM group compared with 24 [15%] of 162 in the SP and 22 [16%] of 136 in the BRCA1 groups; P = .0150), and the proportion of patients with AI increased (five [28%] of 18 in the RM group compared with 15 [83%] of 18 in the SP and 13 [81%] of 16 in the BRCA1 groups; P = .0007). The adjusted odds ratios (OR) for AI in TDLU increased in SP (OR = 15.5) and BRCA1 (OR = 13.7) patients compared with RM (P = .0025). This result was particularly evident on chromosome 17q (P = .0393), where more AI was seen in BRCA1 (OR = 12.4) than in SP (OR = 4.9) patients or RM controls. CONCLUSION Increased prevalence of AI in normal-appearing epithelium is associated with breast cancer and increased breast cancer risk. The increased prevalence may reflect dysregulation, even in normal-appearing epithelium, of genomic processes contributing to cancer development. The clinical significance of genetic alterations in the subset of controls remains to be determined.

Loss of heterozygosity in serial plasma DNA samples during follow-up of women with breast cancer

We evaluated the potential utility of occult circulating tumor DNA as a molecular marker of disease in subjects previously diagnosed with breast cancer. Using 24 microsatellite markers located at sites of frequent loss of heterozygosity (LOH) or allele imbalance in breast cancer, we analyzed DNA from 16 primary tumors (Stage IIA or more advanced) and 30 longitudinally collected plasma specimens. Clinical data at the time of plasma collection were obtained. All 16 tumors were characterized by an individual pattern of LOH. LOH was detected in 12 of 30 (40%) plasma samples, taken from 8 of 14 (57%) subjects. However, the number of LOH in plasma was small (n = 15), and the mean proportion of LOH was much lower than in the tumors (0.05 vs. 0.52). Although infrequent, 12 of 15 (80%) plasma LOH were concordant with abnormalities in the paired tumors, and the mean percent LOH was higher than in normal plasmas, suggesting that they were authentic tumor‐derived abnormalities. We found, despite this, no association, between plasma LOH and tumor stage or clinical status at time of blood collection (i.e., LOH was as common in subjects with no evident disease as in those with evident disease). In addition, detection of LOH was not consistent between serial samples from 5 of 11 subjects (45%), despite stable clinical conditions. No association with clinical outcome was evident, although the sample size was small. Microsatellite instability in plasma was infrequent, nonconcordant with paired tumor and inconsistent in serial samples. This pilot study suggests that identifying tumor‐specific LOH in the plasma of breast cancer subjects may not be useful for detecting occult metastases or for monitoring disease. Other detection techniques may be more promising, but circulating tumor DNA may not be a sufficiently accurate reflection of breast cancer clinical status or tumor activity.

Intraabdominal mesh prosthesis in a canine model

Laparoscopic inguinal hernia repair is still at an investigational stage, and varying methods have been described in the literature. These include the transabdominal preperitoneal approach, the intraperitoneal onlay mesh procedure, and the extraperitoneal approach. This study evaluates the differences in macroscopic adhesion formation between transabdominal preperitoneal mesh placement, intraperitoneal onlay mesh procedures, and extraperitoneal mesh placement in a canine model. The determination of microscopic tissue ingrowth and mesh incorporation was not a goal of this study. Operative sites utilizing mesh in a reperitonealized fashion resulted in less adhesion formation than did those sites where mesh was placed in an intraperitoneal manner using the onlay technique. Mesh placed in the extraperitoneal space without entering the peritoneal cavity did not exhibit any adhesion formation. Results favor the reperitonealization of intraabdominal mesh or mesh placement by an extraperitoneal approach.

Pseudomeningocele as a complication of teratoma resection and aseptic meningitis following craniofacial reconstruction: A case report

This is a report of two extremely unusual complications of craniofacial surgery on a single patient. A 14-year-old female underwent resection of a recurrent teratoma four times within the first 9 years of life. This left her with two large cranial cavities in the left temple and posterior to the orbit communicating with the subarachnoid space constituting a pseudomeningocele and pulsatile mass in the left temple--an unusual complication. Following resection of the pseudoepithelial cavity linings, the spaces were filled with a split temporalis muscle. Two weeks following surgery, she developed signs and symptoms of meningitis with negative cultures from the drain sites and lumbar puncture. Six days following an unsuccessful attempt to treat her with wide spectrum antibiotics, she was treated with dexamethasone. As a result, there was a dramatic disappearance of signs and symptoms in less than 36 hours; she has not experienced any recurrence since. We feel that this aseptic meningitis was the result of cerebrospinal fluid exposure to muscle--a rare, yet, previously reported complication. The details of the case history and discussion of complications and the way in which they can be avoided, are subjects of this report.