Retinoic acid receptor-beta as a prognostic indicator in stage I non-small-cell lung cancer

PURPOSE

Retinoids are pivotal in the growth and differentiation of certain epithelial tissues, interacting with nuclear retinoid receptors (the retinoic acid receptors [RARs] and retinoid X receptors [RXRs]), which function as transcription factors. RAR-beta mRNA is undetectable by in situ hybridization (ISH) in 50% of non-small-cell lung cancers (NSCLC). RAR-beta may suppress tumorigenicity. Therefore, we hypothesized that loss of expression of RAR-beta gene in stage I NSCLC is a prognostic factor of a poor clinical outcome.

PATIENTS AND METHODS

We retrospectively analyzed RAR-beta mRNA levels (by ISH using a digoxigenin-labeled antisense riboprobe) in specimens from 185 consecutive patients with completely resected clinical/radiographic stage I NSCLC for whom clinical follow-up data were available.

RESULTS

One hundred fifty-six patients who met the criteria of pathologic stage I NSCLC and positivity for RXR-alpha mRNA (used as a control to assess RNA degradation) and who had adequate follow-up could be evaluated. RAR-beta mRNA expression was undetectable in 51 patients, weakly positive in 64 patients, and strongly positive in 41 patients. Overall survival of the 41 patients with strongly positive RAR-beta was significantly worse than for the 115 patients with weak or absent RAR-beta (P =.045).

CONCLUSION

Unexpectedly, strong RAR-beta expression was associated with a significantly worse outcome of early-stage NSCLC. The mechanisms underlying this clinically and biologically important finding should be further explored.

Incidence of breast carcinoma in women with thyroid carcinoma

BACKGROUND

Breast carcinoma and differentiated thyroid carcinoma(the most common endocrine malignancy) occur predominantly in women. An association between the two tumors has been suggested by some investigators, but the potential impact of treatment of one of these diseases on the development of the other remains unclear. The authors examined the relation between the occurrence of these two tumors.

METHODS

There were 41,686 patients with breast carcinoma and 3662 with thyroid carcinoma who registered at The University of Texas M. D. Anderson Cancer Center between March 1944 and April 1997. Women who received both diagnoses since 1976 were identified and incidence rates and relative risks of secondary tumor development were calculated. Surveillance, Epidemiology and End Results (SEER) program data on the age-adjusted incidences of these diseases during the same time period were used for the expected incidences in the same population.

RESULTS

Among 18,931 women with a diagnosis of breast carcinoma since 1976, 11 developed differentiated thyroid carcinoma > or = 2 years after the diagnosis of breast carcinoma. These breast carcinoma patients contributed 129,336 person-years of follow-up; the observed incidence of thyroid carcinoma in this group was not different from that in a similar age group of women in the SEER database. Among 1013 women with a diagnosis of thyroid carcinoma since 1976, 24 developed breast carcinoma > or = 2 years after the diagnosis of thyroid carcinoma. These thyroid carcinoma patients contributed 8380 person-years of follow-up; the observed incidence of breast carcinoma in women ages 40-49 years was significantly higher than the expected incidence for women in the same age group in the SEER database.

CONCLUSIONS

Breast carcinoma developing after thyroid carcinoma was diagnosed more frequently than expected in young adult women seen at the study institution since 1976. This potential association and plausible mechanisms of breast carcinoma development after thyroid carcinoma should be evaluated in larger cohorts of patients.

Comparison of MIB-1 (Ki-67) antigen and bromodeoxyuridine proliferation indices in meningiomas

Meningiomas from 40 adult patients were labeled immunohistochemically with monoclonal antibodies to bromodeoxyuridine (BUdR) and the Ki-67 antigen, MIB-1. The meningiomas were classified as classical, or benign (n = 31); atypical (n = 4); or malignant (n = 5). Meningeal sarcomas and hemangiopericytomas were excluded. The patient population consisted of 26 women and 14 men, ranging in age from 26 to 75 years. BUdR proliferation indices ranged from 0% to 5.8%, measurements that were expectedly lower than those for MIB-1, which ranged from 1.5% to 19.3%. MIB-1 proliferation indices were not significantly affected regarding steroid pretreatment or age. These results show a good correlation between the BUdR and MIB-1 proliferation markers (rs = 0.72; P < .0001), which supports the use of anti-MIB-1 as an alternative labeling tool to BUdR for the determination of the proliferation index in meningiomas, thus avoiding the administration of a potentially mutagenic drug.