Distinct array comparative genomic hybridization profiles in oral squamous cell carcinoma occurring in young patients

BACKGROUND

Oral cancer typically affects smokers older than 50 years of age. Recently, however, a marked increase in the number of patients 40 years old and younger, many with no history of tobacco smoking, has been noted. Studies in this age group have so far been restricted to genomic areas well recognized as abnormal in typical patients with oral cancer. The aim of this study was to assess genomic aberrations in oral cancer, using comparative genomic hybridization (CGH) microarray technology, and to compare the genomic aberration profile of patients older than 40 years old with those 40 years old and younger.

METHODS

Tumor samples from 20 patients with oral cancer (age range, 21-78; 10 smokers and 10 nonsmokers) were laser microdissected, and array CGH was used to identify genomic imbalances in these two cohorts.

RESULTS

The older cohort showed high numbers of gains and losses in contrast to very few copy number changes in the younger nonsmoker cohort. In concurrence with the literature, tumors from the older cohort manifested deletions involving 3p and 9p21 and gains involving 3q, 5q, 7p, 8q, 11q, and 20q. The younger group, particularly the nonsmokers, showed very few changes overall, and the aberrations were not in the sites classically associated with oral cancer. Deletion of CDKN2A (p16) was completely absent in the younger group but was present in 50% of the older cohort.

CONCLUSIONS

We have demonstrated that there is far less genomic instability in young nonsmokers with oral cancer than found in typical patients with oral cancer. These observations indicate that oral cancer presenting at a younger age, particularly in nonsmokers, has a genomic profile different from the classically described oral cancer.

Array comparative genomic hybridisation analysis of gamma-irradiated human thyrocytes

The susceptibility of thyroid epithelium to radiation-induced carcinogenesis is well recognised. In this context, thyroid carcinogenesis is associated with specific somatic ret/papillary thyroid carcinoma (PTC) rearrangements and morphologically with the papillary phenotype. Previous studies have demonstrated the possibility of inducing ret rearrangements in vitro using X-rays. The purpose of our study was to assess whether gamma (gamma) radiation using a Caesium 137 source can induce specific ret rearrangements in a human thyroid epithelial cell culture model. We further hypothesised that if radiation-induced thyroid carcinogenesis is associated with non-random rearrangement events, then DNA copy gain and loss induced by irradiation may also occur in a non-random manner. We irradiated SV40-immortalised human thyroid epithelial cells with incremental doses of gamma-radiation and, using TaqMan reverse-transcription polymerase chain reaction, looked for the presence of the common ret rearrangements. Cohorts showing evidence of ret/PTC chimeric transcripts were further analysed using microarray comparative genomic hybridisation (CGH) to detect copy gain and loss associated with radiation. Four Grays of gamma-radiation was sufficient to induce ret/PTC-3. In this model, transcripts of ret/PTC-1 were not detected, and we suggest that the type of radiation may influence the resulting rearrangement that occurs. Using array CGH, we have demonstrated a predominant pattern of subtelomeric deletions occurring in association with this radiation cohort and raise the possibility that chromosome 10 may be a hotspot for radiation-induced damage for as yet unknown reasons.

Autopsy findings in an outbreak of severe systemic illness in heroin users following injection site inflammation: an effect of Clostridium novyi exotoxin?

CONTEXT

An epidemic of unexplained illness among injecting drug users characterized by injection site inflammation and severe systemic toxicity occurred in Ireland and the United Kingdom from April to August 2000. One hundred eight persons became ill, and 43 persons died. In Dublin, 8 of 22 patients died. Six of the 8 fatal cases were epidemiologically linked to a source of heroin. Most had experienced local injection site lesions for 7 to 14 days before developing a rapidly fatal systemic illness characterized by hypotension, thirst, pulmonary edema, pericardial and pleural effusions, and leukocytosis.

OBJECTIVE

To document the clinical course and autopsy findings of the fatal cases in Dublin.

DESIGN

To study the clinical, autopsy, microbiologic, and toxicologic findings from the 8 fatal cases in Dublin.

RESULTS

In Dublin, there were 6 men and 2 women who were fatally involved in the epidemic, with the mean age being 34 years (range, 22-51 years). The injection site inflammations involved the buttock (n = 4), leg, iliac region, arm, and a Portacath site. At autopsy, the local lesions were ulcerated, swollen, and indurated but were inconspicuous in 2 patients. All the deceased had pulmonary edema. There were pleural effusions in 7, 2 of whom had pericardial effusions. Five had prominent left ventricular subendocardial hemorrhages. Five had splenomegaly. Microscopy showed pulmonary edema and a granulocytic reaction mainly in the spleen, marrow, and myocardium. Toxicology showed a range of narcotic drugs in the toxic or fatal range. Clostridium novyi type A, a fastidious toxin-producing anaerobe, was identified in 2 cases.

CONCLUSION

The clinicopathologic findings of a local inflammatory lesion followed 7 to 14 days later by a rapidly fatal systemic illness are consistent with the effect of exotoxin produced by organisms growing in the local inflammatory site. Clostridium novyi-derived exotoxin is the likely cause of such a syndrome, although the fastidious organism was isolated from only 2 of 8 cases (from none of the 14 surviving patients and from only 13 of 60 cases in Scotland). In the setting of an epidemic, the toxic and fatal range blood levels of narcotics are unlikely to explain these events, and no other candidate organism could be isolated. The heroin is likely to have come from Afghanistan, but local contamination at a putative distribution site in the United Kingdom is more likely than international terrorism to be the initiating factor.

Ret/PTC chimeric transcripts in an Irish cohort of sporadic papillary thyroid carcinoma

Ret rearrangements are common in papillary thyroid carcinoma (PTC), with ret/PTC-3 commonly seen in children exposed to ionizing radiation. In this context ret/PTC-3 has been correlated with solid variant morphology, poorer prognosis, and aggressive tumor behavior. We aimed to assess the prevalence of the common ret chimeric transcripts (ret/PTC-1 and ret/PTC-3) in a group of sporadic PTC and correlate them with tumor morphology. Thyroid follicular cells were laser capture microdissected from sections of archival PTC (n = 28). Total RNA was extracted and analyzed for expression of glyceraldehyde 3-phosphate dehydrogenase, ret/PTC-1, and ret/PTC-3 using TaqMan PCR. Ret/PTC rearrangements were detected in 60% of PTCs. Specifically transcripts of ret/PTC-1 and ret/PTC-3 were detected in 43% and 18% of PTCs, respectively. Ret/PTC-3 was detected in only follicular variant subtype (60%) and was not detected in classic PTC. One case of tall cell variant demonstrated chimeric expression of both ret/PTC-1 and ret/PTC-3 transcripts within the same tumor. This study demonstrated a high prevalence of the two common ret rearrangements in an Irish cohort of PTCs. A correlation of tumor morphology with these common ret rearrangements is suggested.