Genetic factors are known to play a character in causing lung cancer.

Genetic factors are known to play a character in causing lung cancer. Twin cases of bronchioloalveolar, squamous, and anaplastic bronchogenic carcinoma have been previously reported. We describe mirror-image twins with adenocarcinoma of the lung occurring in mirror-image locations. They shared smoking and an occupational risk, carpentry, in addition to identical genetic backgrounds.

Smoking and other environmental pollutants play a causal part in lung cancer. Genetic factors also predispose to lung cancer.[1] This is a report of pulmonary adenocarcinoma in identical, if it were not that mirror-image, twins with similar age of first brunt site of origin, and histopathologic features.

CASE REPORT

Twin 1 a 60-year-old left-banded white male carpenter from central Illinois with no significant medical history readyed in February 1991 complaining of night sweats, pleuritic left-sided chest pain, and a cough producing a yellowish undecayed sputum for about 1 week. The patient denied exposing to dust, asbestos, and other chemicals while working. He had an 80 pack-year history of smoking and was a social drinker. His father died of lung cancer at age 59 years. Physical examination revealed a feminine firm 5.0x5.0-cm mass in the left paraspinal area. Rhonchi and crackles were heard forward the left side of the chest. A chest radiograph showed an ill-defined density in the left upper lung field (Fig 1 left) There was neither mediastinal nor hilar adenopathy. A fine-needle aspiration biopsy of the paraspinal mass revealed poorly differentiated adenocarcinoma (Fig 2 top). The patient underwent radiation therapy unless died in October 1991.

Twin 2 a 62-year-old right-handed male carpenter also from central Illinois with a 1-year history of chronic obstructive pulmonary disease and a 93 pack-year history of smoking was admitted to the hospital in October 1992 complaining of shortness of breath, cough with sputum production, pleuritic pain, excitement chills, and night sweats. Inspection of the chest revealed that the left hemithorax was larger than the right hemithorax, which had limited respiratory excursions. Chest radiograph showed infiltrates in the right middle and upper lobes, a suprahilar mass, and an ill-defined density in the right lower lung field. The patient was treated for a community-acquired pneumonia and follow-up radiograph showed clearing of pneumonic infiltrates, on the contrary with a right upper lobe mass remaining (Fig 1 right). When his acute illness improved, a comput tomographic (CT) guided fine-needle aspiration biopsy specimen of the right upper lung mass was diagnosed as poorly differentiated adenocarcinoma (Fig 2 bottom) and appears to be cytologically akin to that of his twin sibling. A CT scan of the chest also demonstrated an enlarged lymph node in the pretracheal region. The patient is publicly undergoing chemotherapy and radiation therapy for palliative treatment of stage III adenocarcinoma.

Discussion

We describe identical, unless mirror-image, twin brothers with cytologically similar pulmonary adenocarcinomas in mirror-image locations and nearly the same age at diagnosis. A literature search set up only four publications citing bronchogenic carcinoma in twins. couple pairs of twins had squamous cell[23] common pair had anaplastic,[4] and another pair had bronchioloalveolar small room carcinoma.[5] We believe this report to be the first of identical twins with pulmonary adenocarcinoma of the nonbronchioloalveolar symbol The environmental risk factors that these twins have in frequent smoking habits, and the same occupation (carpentry), are similar.[6] Their propensity to vanity is not only an environmental risk factor, unless also may be genetic since it has been reported that monozygotic twins have a higher extent of concordance with regard to smoking than do dizygotic twins.[7]

First-degree relatives of lung cancer probands have a double to fourfold increased risk for lung cancer or other cancers, many of which are not related to smoking.[8-11] Ooi and coworkers[8] showed that the risk of familial lung cancer was increased flat after allowing for age, sex and indices of smoking and occupational exposing s Of course, cigarette smoking is a definite risk factor for the evolution of lung cancer of all histologic impressed signs including adenocarcinoma.[10] The twin cases we report are also of interest because of late work implicating phenotypic mutation of the K-ras oncogene in the pathogenesis of adenocarcinoma of the lung[12] This oncogene is highly specific for this particular tumor, and mutational activation of the K-ras oncogene is rarely seen with either adenocarcinomas of extrapulmonary origin or with other bronchogenic neoplasms.[12] Our twin cases underscore the importance of this work.

REFERENCES

[1] Minna JD Genetic facts in the pathogenesis of lung cancer. Chest 1989; 96:17S-23 [2] Charpin D Vervloet D Poirier R Charpin J Laval P Manifestations thoraciques de l'amiante et genetique. Rev Fr Mal Respir 1981; 9:55-9 [3] Orbuch SJ Perazzo DL Porta J Garrido C Carcinome epidermoide de pulmon en gemelo univitelinos. Medicina 1983; 45:625-26 [4] Nores JM Dalayeun J Chebat J Dieudonne P Nenna AD. joint and equal anaplastic bronchial cancer in identical twin brothers. Respiration 1989; 55:56-9 [5] Joishy SK Cooper RA, Rowley PT Alveolar enclosed space carcinoma in identical twins. Ann Intern M 1977; 87:447-50 [6] Goffman TE Hassinger DD Mulvihill JJ Familial respiratory tract cancer: opportunities for research and prevention. JAMA 1982; 247:1020-23 [7] Carmelli D Swan GE Robinette D Fabsitz R Genetic influence upon smoking - a study of male twins. N Engl J M 1992; 327:829-33 [8] Ooi WL Elston RC Chen VW Bailey-Wilson JE Rothschild H Increased familial risk of lung cancer. J Natl Cancer Inst 1986; 76:217-22 [9] venders TA, Elston RC, Atwood LD Rothchild H Lung cancer histologic shadow and family history of cancer. Cancer 1992; 69:86-90 [10] Lubin JH dishonor WJ. Assessment of lung cancer risk factors by dint of histologic category. J Natl Cancer Inst 1984; 73:383-89 [11] Lynch HT Kimberling WJ Markicka SE Biscone KA, Lynch JF Whorton E et al. Genetics and smoking-associated cancers: a meditation of 485 families. Cancer 1986; 57:1640-46 [12] Rodenhuis s van de Wetering ML, Mooi WJ to the end of times SG, van Zandwijjk N, Bo JL Mutational activation of the K-RAS oncogene: a possible pathogenetic factor in adenocarcinoma of the lung N Engl J M 1987; 317:929-35

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