Long-term subjective results of Marshall-Marchetti-Krantz procedure

OBJECTIVE

Retrospective, subjective evaluation of results of suprapubic vesicourethropexy (Marshall-Marchetti-Krantz procedure) for stress urinary incontinence.

MATERIAL

A total number of 81 patient records operated between 1980 and 1994 at our institution were reviewed and questionnaires were mailed to them to estimate the success rate, period of continence, current complaints and patient satisfaction. Patients with primary incontinence constituted 73% of this group, the remainder of 27% being recurrent or persistent incontinence.

RESULTS

The response rate was 75% (60 cases) and this group was evaluated. Mean postoperative time was 9.9 (2-15) years at the time of assessment. Mean duration of continence was 78.5 months and was not influenced by prior hysterectomy or parity. Weak correlation was found between patients' age and continence period. It was similar in patients operated in their 5th and 6th decades of life and was shorter in the 7th decade. Additional sutures placed between the anterior bladder wall and rectus fascia (Lapides modification) resulted in a longer continence period. Cure rates decreased with time and were 81, 77, 57 and 28% after 6, 12, 60 and 120 months respectively. In the incontinent group, 34% of patients described leakage degree as lesser than preoperatively and 65% required protection. As many as 90% of continent and 62% of incontinent women evaluated their urinary system status as better than preoperatively. 90% of continent and 69% of incontinent women would repeat surgery again.

CONCLUSIONS

This procedure is characterized by a high 81% early postoperative success rate that decreases with time. Despite recurrence of stress incontinence, one third of patients declare lesser incontinence degree and do not require protection.

Induction of prostate apoptosis by doxazosin in benign prostatic hyperplasia

PURPOSE

The molecular mechanisms underlying the therapeutic effect of the alpha1 blocker, doxazosin, on benign prostatic hyperplasia (BPH) are poorly understood. We evaluated the effect of doxazosin on cell proliferation and apoptosis in the prostatic glandular epithelium and stroma of patients with BPH.

MATERIALS AND METHODS

We examined proliferative and apoptotic activities in prostate specimens of 22 men a mean of 65 years old with BPH before and after doxazosin treatment within the normal therapeutic range. Proliferative and apoptotic indexes were determined using Ki-67 nuclear antigen staining and the terminal transferase end labeling assay, respectively. The smooth muscle cell content in prostatic specimens was identified by smooth muscle alpha-actin, and desmin immunoreactivity and apoptotic indexes were correlated with prostatic stromal tissue regression and improvement in BPH symptoms.

RESULTS

In response to doxazosin treatment there were no significant changes in the kinetics of cell proliferation in the prostatic epithelial or stromal cell population. Mean pretreatment baseline apoptosis was 1.9 and 1.0% for the epithelial and stromal prostate components, respectively. Mean apoptotic indexes significantly increased after 3 months of doxazosin treatment in the glandular epithelial (6%) and smooth muscle cells (15%). By 12 months after treatment epithelial apoptosis had decreased to constitutive levels, while the apoptotic index of prostatic stroma cells remained high. Doxazosin induced smooth muscle cell apoptosis correlated with prostatic stromal degeneration, decreased alpha-smooth muscle actin expression and improved BPH symptoms.

CONCLUSIONS

These findings implicate the induction of prostate apoptosis by doxazosin as a potential molecular mechanism underlying the acute and chronic therapeutic responses of BPH to alpha1 blockade.

Induction of prostate apoptosis by doxazosin in benign prostatic hyperplasia

PURPOSE

The molecular mechanisms underlying the therapeutic effect of the alpha1 blocker, doxazosin, on benign prostatic hyperplasia (BPH) are poorly understood. We evaluated the effect of doxazosin on cell proliferation and apoptosis in the prostatic glandular epithelium and stroma of patients with BPH.

MATERIALS AND METHODS

We examined proliferative and apoptotic activities in prostate specimens of 22 men a mean of 65 years old with BPH before and after doxazosin treatment within the normal therapeutic range. Proliferative and apoptotic indexes were determined using Ki-67 nuclear antigen staining and the terminal transferase end labeling assay, respectively. The smooth muscle cell content in prostatic specimens was identified by smooth muscle alpha-actin, and desmin immunoreactivity and apoptotic indexes were correlated with prostatic stromal tissue regression and improvement in BPH symptoms.

RESULTS

In response to doxazosin treatment there were no significant changes in the kinetics of cell proliferation in the prostatic epithelial or stromal cell population. Mean pretreatment baseline apoptosis was 1.9 and 1.0% for the epithelial and stromal prostate components, respectively. Mean apoptotic indexes significantly increased after 3 months of doxazosin treatment in the glandular epithelial (6%) and smooth muscle cells (15%). By 12 months after treatment epithelial apoptosis had decreased to constitutive levels, while the apoptotic index of prostatic stroma cells remained high. Doxazosin induced smooth muscle cell apoptosis correlated with prostatic stromal degeneration, decreased alpha-smooth muscle actin expression and improved BPH symptoms.

CONCLUSIONS

These findings implicate the induction of prostate apoptosis by doxazosin as a potential molecular mechanism underlying the acute and chronic therapeutic responses of BPH to alpha1 blockade.

p21waf1/cip1 and transforming growth factor beta 1 protein expression correlate with survival in non-small cell lung cancer

p21waf1/cip1 encodes a cyclin-dependent kinase inhibitor that is transcriptionally activated by the p53 tumor suppressor gene, transforming growth factor beta 1 (TGF-beta 1), AP2, and other pathways. Because p21waf1/cip1, p53, and TGF-beta 1 all regulate apoptosis and the cell cycle, we tested the hypothesis that their relative protein levels would correlate with biological features including the survival of non-small cell lung cancer (NSCLC) patients. We conducted an immunohistochemical analysis of p21waf1/cip1 and TGF-beta 1 and identified four patient groups with distinct survival outcomes. Concordant p21waf1/cip1 and TGF-beta 1 expression (i.e., either high p21waf1/cip1 and high TGF-beta 1 expression or low p21waf1/cip1 and low TGF-beta 1 expression) predicted 70% disease-free survival at 2000 days of follow-up. Discordant p21waf1/cip1 and TGF-beta 1 expression (i.e., either high p21waf1/cip1 and low TGF-beta 1 expression or low p21waf1/cip1 and high TGF-beta 1 expression) predicted 35% disease-free survival (P = 0.0003; log-rank test). These survival relationships were not attributable to differences in grade, stage, or p53 status. Although current models do not fully explain these complex interactions, most of these data fit a paradigm whereby TGF-beta 1 regulation determines NSCLC survival. In addition to the survival correlation, we found that high p21waf1/cip1 protein expression correlated with high tumor grade (P = 0.014). There is little evidence that p21waf1/cip1 protein levels accurately predict p53 mutation status in NSCLC; specifically, 20 of 48 (42%) tumors with p53 mutations contained high levels of p21waf1/cip1 protein. These findings indicate that p21waf1/cip1 immunohistochemical analysis may provide useful information concerning the biological properties of NSCLC.

[Urinary diversion to the large intestine in adults]

The paper presents the history of technique and concepts of urinary diversion to colon and rectum from the mid-XIXth century until today, including the contribution of Polish surgeons--Kryński, Laskownicki and Kiełkiewicz. Contraindications and complications of this type of definitive urinary diversion is briefly discussed. Authors also present the outcome of ureterosigmoidostomy performed according to method proposed by Goodwin in 25 patients cystectomized for infiltrating transitional cell carcinoma of the bladder, who were operated on at the Department of Urology, Medical School in Warsaw. These patients were in poor general condition and short life expectancy, which depended upon tumour stage and grade as well as preoperative urographic evaluation of urinary tract.

Concentration of copper and zinc in blood of psoriatic patients treated topically with ointment containing 2-chloroethyl-3-chloropropyl sulfide

Copper and zinc concentration in plasma, erythrocytes and whole blood was determined in a group of psoriatic patients (n = 80 ) before and after treatment with an ointment (in accordance with recommendations of the Helsinki Declaration) in which 2-chloroethyl-3-chloropropyl sulfide (CLEPS) is an active compound and in a comparative group (n = 99) of clinically healthy volunteers. The performed examinations revealed a significantly lower (by 19.1%) plasma copper concentration in patients before treatment in comparison with the control group. After treatment (CLEPS) plasma copper concentration increased significantly (p < 0.001). In comparison with the control group, in erythrocytes of psoriatic patients copper concentration was higher both before and after treatment. Plasma zinc concentration in psoriatic patients was lower before treatment, whereas in erythrocytes, compared with the control group, it was higher both before and after treatment.

Loss of the cyclin-dependent kinase inhibitor p27(Kip1) protein in human prostate cancer correlates with tumor grade

Loss of expression or mutational deletion of the cyclin-dependent kinase inhibitor p27(Kip1) has recently been implicated in malignant development. In this study, we investigated the relationship between p27(Kip1) protein expression and tumor grade in human prostate cancer by conducting an immunohistochemical analysis in a series of normal prostate, benign prostatic hyperplasia, and malignant prostate cancer specimens. The proliferative activity of prostatic tumors was determined on the basis of the Ki-67 nuclear antigen staining. A uniformly intense immunoreactivity for p27(Kip1) was localized to the nuclei of glandular epithelial cells of normal prostates. The benign glandular epithelia exhibited moderate immunostaining. In the malignant prostate tissue, however, a heterogeneous pattern of substantially reduced p27(Kip1) immunoreactivity was found among the glandular epithelial cells. The majority of primary prostate cancer specimens (68%) were totally negative for p27(Kip1) immunoreactivity, whereas the rest exhibited a significantly decreased p27(Kip1) expression, compared with the normal prostate (P < 0.01). Moreover, there was progressively diminished p27(Kip1) immunostaining with increased tumor grade. This loss of p27(Kip1) was associated with an increase in the proliferative index of prostatic tumors (r = 0.88). There was no significant relationship between p27(Kip) loss and the transforming growth factor beta receptor status of prostatic adenocarcinomas. These results indicate that frequent loss of the cyclin-dependent kinase inhibitor p27(Kip1) in human prostate cancer cells correlates with advancing histological aggressiveness, implicating deregulation of p27(Kip1) in prostate tumor progression.

Natural antiestrogen receptor autoantibodies in man with estrogenic activity in mammary carcinoma cell culture: study of their mechanism of action; evidence for involvement of estrogen-like epitopes

We previously reported that human natural autoantibodies enriched in antiestrogen receptor Ig (IgGs) display estrogenic activity in MCF-7 mammary carcinoma cells. In this study, we investigated IgGs' mechanism of action. We showed that: 1) IgGs Fab fragments (which contain only one antigen binding site) induced an estrogenic response in MCF-7 cells, producing estrogen receptor (ER) down-regulation and an increase in progesterone receptor concentration; 2) IgGs specifically inhibited MCF-7 cell surface labeling with fluorescent estradiol (E2)-BSA conjugates; 3) this inhibition of E2-BSA binding to membrane estrogen binding sites was largely caused by natural anti-E2-BSA antibodies (Ab) selectively associated with the natural anti-ER Ab within IgGs; 4) furthermore, these natural anti-E2-BSA Ab accounted for most of IgGs estrogenic activity in cell culture; 5) however, when incubated with cytosolic ER, they did not behave like estrogens, but they decreased ER hormone binding capacity; and 6) although IgGs stimulated cAMP production, their anti-E2-BSA Ab subpopulation did not. In conclusion, the estrogenic activity of IgGs does not involve Ab mimicking E2 molecular configuration or ligand-independent cAMP mediated pathways, membrane Fc receptors, and membrane receptor cross-linking mechanisms. On the contrary, IgGs seem to function by neutralizing estrogen-like epitopes, associated with ER-related peptides, which might inhibit ER activation.

[Diagnosis and treatment of vesicouterine fistula occurring after cesarean section]

Eleven cases of vesicouterine fistula were reported. The initial diagnosis was made when urinary incontinence was occurring. The diagnosis was best confirmed by cystoscopy and hysterography, which was positive in 9 cases. The ultrasonographic examinations allow to visualize the fistula in 5 out of 6 cases examined and to establish the diagnosis. If sonographic examination visualizes the fistula, the performing of hysterography is not necessary. The management consists of the cure of the infection of the urogenital tract and abdominal operation based on the excision of the fistula and closing of the bladder and uterus. All operated patients were cured.

Integrity of p53 in hepatitis B x antigen-positive and -negative hepatocellular carcinomas

Inactivation of the tumor suppressor p53 seems to be important to the pathogenesis of hepatocellular carcinoma (HCC) associated with chronic hepatitis B virus infection. Although this inactivation may be due to mutations in the p53 gene, recent evidence suggests that the hepatitis B virus-encoded X antigen (HBxAg) binds to and inactivates wild-type p53. Hence, experiments were designed to test the hypothesis that there is a low frequency of p53 mutations in HBxAg-positive HCC. HBxAg and p53 were assayed by immunohistochemistry (IHC) in HCC and nontumor liver from 16 Chinese patients, half of whom were hepatitis B surface antigen carriers. HBxAg was detectable in tumor and/or nontumor cells from all patients by IHC; six of these samples also had detectable p53. To determine whether p53 detection by IHC, and hence stabilization, is associated with mutation, sequencing of p53 exons 5-8 was performed with each patient sample. Wild-type sequences were found in 13 of 16 HBxAg-positive cases (81%). Hence, HBxAg is a common marker of HCC that correlates with the persistence of wild-type p53 among both carriers and noncarriers. The low frequency of p53 mutations in HCC in these patients implies that p53 inactivation may occur predominantly by complex formation with HBxAg.

Relationship between semen quality improvement after varicocelectomy and preoperative levels of hypophyseal and gonadal hormones

Evaluation of serum levels of FSH, LH, prolactin, testosterone and oestradiol is not predictive of the increases of sperm count after varicocelectomy. Increased level of oestradiol reflects the lack of possibility of sperm motility increase after varicocelectomy.

Elevated prostate-specific antigen levels in black men and white men

The usual ranges for prostate-specific antigen (PSA) are derived from a community-based population of White men but are used for screening on all men on the assumption that the differences between the PSA levels of different racial groups are small or have no clinical significance. Recently published reports, however, suggest that PSA levels in a specific racial population may vary directly with the relative risk of prostatic cancer within that population. PSA ranges were determined in Black and White men registered with the Veterans Affairs Maryland Health Care System, Baltimore, Maryland. The total patient census of 122,602 has near-equal numbers of Black and White men and maintains records of race designation for inpatients. Among the male patients with no known prostatic cancer, there were 10,808 men 40 years of age or older and 19,482 PSA test results. In this group, there were 3274 men identified as Black; 2993 identified as White, Not of Hispanic Origin, and 4541 identified as Other Race or Race Unknown. The 95th percentile PSA values in Black men and White men 40 through 49 years of age were 2.80 ng/mL and 2.01 ng/mL, respectively; 50 through 59 years old, 5.40 ng/mL and 4.19 ng/mL, respectively; 60 through 69 years old, 9.59 ng/mL and 7.00 ng/mL, respectively; 70 through 79 years old, 15.45 ng/mL and 9.40 ng/mL, respectively; and for men older than 80 years of age, the 95th PSA values were 21.05 ng/mL in Black men and 18.25 ng/mL in White men. In every age group, Black men had a higher range (for the 95th percentile) than did White men. The largest difference was found in men 70 through 79 years old; in this age group, the ratio of the upper limit of PSA for Black men compared with White men was 1.6 ng/mL.

Incidence of apoptosis and cell proliferation in prostate cancer: relationship with TGF-beta1 and bcl-2 expression

The incidence of programmed cell death (apoptosis) and cell proliferation was investigated in the normal and malignant human prostate to define the significance of their potential deregulation in human prostate cancer. The incidence of "spontaneous" apoptosis was analyzed using an in situ end-labeling procedure for detection of nucleosomal DNA fragmentation, as well as the pattern and topological localization of expression of the 2 proteins regulating apoptosis, TGF-beta1, and bcl-2, in 40 primary prostatic adenocarcinomas with varying tumor grades, 17 lymph nodes positive for metastatic prostate cancer and 9 normal prostate specimens. The basal level of cell proliferation of the different prostatic cell populations in the same specimens was determined, utilizing the Ki-67 nuclear antigen. Localized prostate cancer cells exhibited a relatively low rate of apoptosis, which was significantly lower than the apoptotic index of normal prostate glandular epithelial cells. Metastatic prostate tumor cells, however, exhibited a significantly higher apoptotic index compared with localized prostate cancer cells. A significant increase in the proliferative index was detected in prostatic tumors compared with the normal gland (5-fold), and there was an even more marked elevation in the proliferative index of the metastatic prostate tumor cells compared to the normal prostate epithelial cells (approximately 24-fold). Immunohistochemical analysis of normal and malignant prostate specimens revealed a predominant TGF-beta immunoreactivity in the glandular epithelial cells, while the stromal component was totally negative. There was a significant increase in the levels of TGF-beta in primary prostatic tumors compared to the normal prostate. Bcl-2 expression was detected among certain populations of tumor epithelial cells in a mutually exclusive topological distribution pattern for apoptosis. In marked contrast, neither TGF-beta1 nor bcl-2 immunoreactivity was detected in metastatic prostate tumor cells, despite their high proliferative and apoptotic rates. Balancing the prostatic growth equation for the prostatic tumor epithelial cell populations revealed a substantial net increase in cell number in both primary and metastatic prostate cancers. This loss of apoptotic control in favor of cell proliferation may be responsible for prostate cancer initiation and progression.

Restoration of the continuity of dog ureter after resection of its 5 cm middle segment

OBJECTIVE

To evaluate the restoration of the ureter of the dog after resection of a 5 cm-long middle segment.

MATERIALS AND METHODS

Eight dogs underwent resection of the middle segment of the ureter, after which a 6-8 F Bard ureteric stent modelling catheter was inserted into both remaining portions of the ureter for 3 months. One month after removal of the stent the animals were killed and their ureters examined both grossly and microscopically. Paraffin-embedded sections were subjected to microscopic and immunohistochemical studies.

RESULTS

The continuity of the ureter was restored but the reconstructed segment was narrowed to a variable extent. The wall of the ureter was lined by normal urothelium but consisted of fibrous connective tissue which failed to produce a regular coat. The reconstructed segment showed no smooth muscle cells (negative staining with azan and a negative reaction with monoclonal antibodies against desmin). A few smooth myocytes were found only at the border with intact portions of the ureter.

CONCLUSIONS

The surgical procedure resulted in the restoration of ureteric continuity by repair and not by regeneration of its wall.

Quantitative image analysis of p53 protein accumulation in keratoacanthomas

Keratoacanthomas are benign skin tumors that grow rapidly but eventually regress. They occur most commonly in sun-exposed skin and are histologically remarkably similar to squamous cancers. Since mutations of the p53 tumor suppressor gene are found frequently in cutaneous squamous cell carcinomas, we hypothesized that p53 mutations might contribute to the development of keratoacanthomas. To address this question, we did p53 immunohistochemistry with a polyclonal rabbit antiserum, CM-1, that binds both mutant and wild-type p53 proteins. Although wild-type p53 protein degrades rapidly and is generally undetected by immunohistochemistry, mutant p53 protein has a longer half-life and accumulates to detectable levels. We tested 26 formalin-fixed keratoacanthomas and 4 normal skin biopsies. Positive nuclear staining was detected in 20 of 26 (77%) of the keratoacanthomas and in none of the normal skin samples. Nuclear staining occurred in the outermost layer of the neoplasms and not in the keratin-filled central cores. Since nuclear p53 protein within a cutaneous squamous cell carcinoma usually correlates with missense mutation, these data suggest that p53 mutations contribute to the development of this benign neoplasm. The histologic similarity to squamous cell carcinoma and the accumulation of p53 protein suggest progression toward malignancy, but the invariable regression of these tumors suggests an arrest at some point in multistage carcinogenesis. If this model is correct, then genetic analysis of keratoacanthomas may provide clues to the later stages of squamous carcinogenesis including local invasion and metastasis.

Studies on TGF-beta 1 gene expression in the intima of the human aorta in regions with high and low probability of developing atherosclerotic lesions

Certain regions of the human aorta are at greater risk for early and more severe atherosclerotic lesions development than others. Cornhill and coworkers (Cornhill FJ et al.: Arteriosclerosis 5:415, 1985) created maps for the probability of developing atherosclerosis defining the high-probability region (HPR) in the dorsal descending thoracic aorta and the low-probability region (LPR) in the ventral descending thoracic aorta. Our study examines the hypothesis that transforming growth factor beta -1 (TGF-beta 1), a well-known suppressor of growth and function in many human cell lines, is one of the inhibitors of human atherogenesis. The present experiment analyzes the expression of mRNA for TGF-beta 1 in both the HPR and the LPR of aortas from young (age 17 to 25 y) males of black (n = 8) and white (n = 7) race. The level of TGF-beta 1 gene expression was assessed in the aortic intima in both the HPR and the LPR, using National Institutes of Health Image 1.47, an Apple Macintosh application capable of digital image processing, analysis, and morphometric measurement. There was significantly lower (P = 0.002, alpha = 0.05) TGF-beta 1 gene expression in the HPR than in the LPR in the 22- to 25-y age group. There was no significant difference in the 17- to 21-y age group and between the HPR and the LPR in the entire study group.(ABSTRACT TRUNCATED AT 250 WORDS)

Urethral stricture as unusual complications of Wegener's granulomatosis

A patient with Wegener's granulomatosis is reported. The diagnosis was confirmed by parotid gland biopsy. The patient responded to treatment with cyclophosphamide and prednisone. After many years, urethral stricture and subglottic stenosis developed and responded satisfactorily to surgery.

Impact of unfunded research in medicine, pathology, and surgery

The impact of unfunded medical research (ie, research conducted with no visible means of support) has received scant attention. In this study, we counted research contributions from the 10 most-cited journals in the fields of internal medicine, pathology, and surgery. Ten consecutive articles, excluding case reports and review articles, for the years 1987, 1989, and 1991 were sampled from each of 10 journals for the three areas of medicine. Unfunded articles accounted for the majority of contributions (60% of pathology articles, 62% of internal medicine articles, and 74% of surgery articles). In 1987, funded research articles published received somewhat more citations (2,961) than unfunded research articles (2,368). Among articles supported by an NIH grant, the first author of the article was seldom the grant's principal investigator (38.6%, 26.9%, and 16.7% of funded articles by pathologists, internists, and surgeons, respectively). These results indicate that unfunded research plays a major role in medical research.

Resection of the liver in a metastatic disease caused by renal carcinoma

Two patients are presented who had their livers resected because of the metastasis of the kidney tumour. It is a contribution in the discussion on the possibility of treatment of a well-advanced cancer disease. The treatment chosen was possible because of the close co-operation between two different teams of surgeons.

Combined extracts of Urtica dioica and Pygeum africanum in the treatment of benign prostatic hyperplasia: double-blind comparison of two doses

The 134 patients (aged 53 to 84 years) with symptoms of benign prostatic hyperplasia were drawn from two medical centers in Warsaw. The patients were randomly assigned to receive two capsules of the standard dose of an urtica/pygeum preparation (300 mg of Urtica dioica root extract combined with 25 mg of Pygeum africanum bark extract) or two capsules containing half the standard dose twice daily for 8 weeks. After 28 days' treatment, urine flow, residual urine, and nycturia were significantly reduced in both treatment groups. After 56 days' treatment, further significant decreases were found in residual urine (half-dose group) and in nycturia (both groups). There were no between-group differences in these measures of efficacy. Five patients reported adverse effects of treatment; treatment was not discontinued in any patient because of side effects. It is concluded that half doses of the urtica/pygeum extract are as safe and effective as the recommended full doses.

p53 protein accumulates frequently in early bronchial neoplasia

p53 mutations are common in human lung cancer and frequently generate levels of p53 protein that are detectable by immunohistochemistry. For this reason, p53 protein accumulation is a candidate biomarker, but little is known about its timing or frequency in multistage bronchial carcinogenesis. We studied human lung tissues containing preinvasive squamous neoplasms from 34 donors with and without lung cancer. Nuclear p53 protein was present in 0% of normal mucosas, 6.7% of squamous metaplasias, 29.5% of mild dysplasias, 26.9% of moderate dysplasias, 59.7% of severe dysplasias, 58.5% of carcinomas in situ, 67.5% of microinvasive carcinomas, and 79.5% of invasive tumors. These data indicate that (a) p53 protein accumulates in about 30% of the earliest recognized neoplastic lesions (i.e., mild dysplasia), (b) there is an increasing frequency of p53 protein accumulation starting with mild dysplasia, and (c) p53 protein accumulates infrequently in normal or metaplastic mucosa. In a subset of six patients whose most advanced lesion was carcinoma in situ without evidence of invasive cancer, p53 protein was detected in 0% of normal mucosas, 8.3% of squamous metaplasias, 37.5% of mild dysplasias, 12.5% of moderate dysplasias, 93.8% of severe dysplasias, and 55% of carcinoma in situ lesions. These data show clearly that p53 alterations can occur before invasion and suggest that the frequency is similar to that observed in the full series. Since two-thirds or more of lung cancers have p53 alterations, the timing and frequency of p53 protein accumulation make the p53 tumor suppressor gene an attractive marker for early diagnosis and evaluation of chemoprevention agents.