Low p27 expression correlates with poor prognosis for patients with oral tongue squamous cell carcinoma

BACKGROUND

p27, a cyclin-dependent kinase inhibitor, regulates progression from G1 to S phase. There have been a few clinical reports of low p27 expression associated with poor survival among patients with cancer; however, there have been no reports of such an association in cases of head and neck cancer. The authors investigated whether p27 expression in patients with oral tongue squamous cell carcinoma was associated with their prognosis.

METHODS

Ninety-four patients with oral tongue squamous cell carcinoma were analyzed. The authors performed p27 immunohistochemistry on all patients and Western blot analysis on 19 available patients. Cox proportional hazards regression analysis that included gender, history of smoking and alcohol usage, presence of multiple primary cancers, stage, histologic grade, and p27 status was used to identify the multivariate predictive value of prognostic factors.

RESULTS

Twenty-six patients had high p27 expression (> or =50% tumor cell nuclei positive), and 68 patients had low p27 expression (<50%) by immunohistochemistry. In those with low p27 expression, N(+) and advanced T (T3 or T4) were significantly higher than in those with high p27 expression (P = 0.02 and 0.04). The 5-year survival rate in the low p27 group was 44%, whereas that in the high p27 group was 68%, indicating a significant difference (P = 0.04). p27 expression was inferred from Western blot analysis, and an arbitrary quantity (<1, 1-5, or > or =5) from the ratio of tumor to normal tissue density was used to characterize, resulting in 8 (42%), 3 (16%), and 8 (42%) patients in the low (<1-fold), intermediate (1-5-fold), and high (> or =5-fold) groups, respectively. Results of immunohistochemical analysis for p27 were significantly correlated with those of Western blot analysis (P = 0.02). Multivariate analysis revealed that low intensity of p27 expression and advanced stage (Stage III or IV) were predictors of reduced survival (P = 0.02 and 0.001).

CONCLUSIONS

Low p27 expression was associated with increasing lymph node metastasis and stage of tumor and resulted in a poor prognosis for patients with oral tongue squamous cell carcinoma. p27 is apparently a significant predictor of survival.

Amplification of cyclin D1 in squamous cell carcinoma of the head and neck and the prognostic value of chromosomal abnormalities and cyclin D1 overexpression

BACKGROUND

Abnormalities of chromosome band 11q13 are frequent in squamous cell carcinoma of the head and neck (SCCHN). The oncogene CCND1 is located at 11q13 and encodes cyclin D1, a cell cycle-regulating protein. The authors investigated the clinical relevance and associations between amplification and overexpression of cyclin D1 and 11q13 rearrangements.

METHODS

The study involved two series of patients. In Series 1, overexpression of cyclin D1 and 11q13 rearrangements, assessed by immunohistochemistry and cytogenetics, respectively, were compared with clinical data in 75 patients with SCCHN. Patients were monitored for at least 18 months or until death. In another 23 patients (Series 2), the authors investigated the association between DNA amplification (by slot blot hybridization), overexpression of cyclin D1, and cytogenetics.

RESULTS

In Series 1, 9 of 75 tumors (12%) had 11q13 aberrations, 6 of which manifested elevated expression of cyclin D1. Patients with tumors strongly positive for cyclin D1 (n = 9) and those with tumors showing 11q13 rearrangements had poorer survival (P = 0.047 and 0.005, respectively). However, the correlation between these two variables was weak (P = 0.12). In Series 2, 17 of 23 tumors (74%) showed elevated cyclin D1 protein expression, and 6 of these showed gene amplification as well. Of these six, only one revealed 11q13 rearrangements.

CONCLUSIONS

Overexpression of cyclin D1 and 11q13 rearrangements are independent prognostic factors for SCCHN. In general, DNA amplification results in overexpression of cyclin D1, but additional genetic mechanisms are involved in the deregulation. Furthermore, oncogenes at 11q13 besides CCND1 may be involved in the tumorigenesis.

Kaposi's sarcoma: a trifactorial model

To explain the epidemiology of Kaposi's sarcoma, including its predominance in men, I present a theory based on three concurrent factors: immunodeficiency, exposure to a specific viral agent, and a recessive, highly prevalent X-linked regulatory gene. The X-linked locus is inferred from comparing the aberrant lymphaticovenous nature of immature lesions with absence of lymphaticovenous connections in XO karyotypes. The theory predicts that for heterosexual populations without sex differences in viral exposure or degree of immunodeficiency, the male-to-female ratio of Kaposi's sarcoma will equal the inverse of the lesion's frequency causative virus. In addition, an increased incidence of Kaposi's sarcoma is expected outside of the context of the acquired immunodeficiency syndrome as the causative virus is transmitted separately from the human immunodeficiency virus.